Female sexual dysfunction (FSD) is a term which is used when dissatisfaction with your sex life is causing you real unhappiness or distress. It includes problems with sex drive, with getting aroused and with achieving orgasm, but it also covers sex which is uncomfortable or painful.
What is female sexual dysfunction?
Female sexual dysfunction (FSD) occurs when you are unhappy with your sex life. This can mean that your sex drive is lower than you would like, that you find it difficult to become aroused or reach orgasm, or that sex is uncomfortable or painful. It may be a combination of some or all of these. The term FSD is usually used when the problems you experience have been going on for six months or more: some women with FSD say that their sex lives have always been unsatisfying enough to cause them unhappiness or distress.
FSD is not an illness, although it is a problem which can cause great unhappiness (and for which there are a number of treatments). Some women experience FSD for their whole lives, whereas for others it can come because of illness, life experiences, with ageing or for no apparent reason. It may occur in every situation (and with every partner), or only in some situations or with some partners. It may resolve by itself, or it may need help.
What types of female sexual dysfunction are there?
Doctors group FSD into three main types of symptom. They are:
- Sexual interest/arousal disorder: you have reduced or absent interest in sex, reduced responsiveness to sexual situations, reduced erotic thoughts or masturbation, and/or reduced pleasure in sex.
- Female orgasmic disorder: you don't or can't have orgasms, have difficulty having orgasms (or find they are very delayed), or you have a reduction in the intensity of orgasm.
- Genito-pelvic pain/penetration disorder: you have difficulty with vaginal penetration, pain during penetration, fear or anxiety about pain before, during, or after penetration, or tightening or tensing of pelvic floor muscles which prevent penetration when you try.
If you have serious mental health problems, are experiencing severe relationship distress (such as domestic violence) or have other reasons to be extremely distressed, such as bereavement, you would not normally be given a diagnosis of FSD as well, as these disorders are likely to impact seriously on your sexual function.
What is the Female Sexual Function Index?
This is a questionnaire that you can do online to assess FSD. There are 19 questions and it may be helpful to complete the questionnaire and take it with you if you are planning to discuss your problems with a health professional. There is a link to the Female Sexual Function Index in the references below.
How common is female sexual dysfunction?
It is difficult to be certain but it is thought that around 4 in 10 of all women and more than 8 out of every 10 postmenopausal women experience FSD.
What is normal female sexual function like?
All women are different, and what matters in respect of FSD is whether or not your sex life is satisfactory for you. For most women a satisfactory sex life involves desire, arousal and sexual pleasure, sometimes/often followed by orgasm, without significant discomfort. Most women also do not consider sex completely satisfactory without significant emotional connection with their partner.
Sexual response comes from a mixture of emotional, psychological and physical factors.
- Emotional factors include intimacy, comfort, attraction, excitement and trust.
- Psychological factors include mood, self-esteem and body image, and stress.
- Physical factors include general health and fitness, blood supply, hormone levels, nerves in the genital area, spinal cord and brain, and general levels of flexibility, pain and wellness. The clitoris, vaginal wall and pelvic floor are all important in arousal and orgasm.
- Personal, individual and attitude factors, such as previous experience, expectation, culture, moral and religious views, shyness and confidence, and the importance you attach to things like familiarity, trust, excitement and risk.
Sexual function in women is not an exact mirror of that in men. In men sexual experience tends to progress in a fixed order - libido and arousal come first, erection follows arousal and, after the right stimulation (and with the right emotional factors in place), orgasm follows erection. In women, however, the sexual response cycle is not always orderly like this, and libido, excitement, pleasure and orgasm don't necessarily occur in a fixed order. For example, women may want or initiate sex for emotional or intimacy reasons rather than because of physical arousal, so arousal may begin during sex and after sexual enjoyment begins, rather than coming first. Women can also enjoy sex yet have a low sex drive. Most women do not need to reach orgasm all the time for a satisfactory sex life, but most women in surveys viewed a sex life without any orgasm as unsatisfactory. Many women do not achieve orgasm through penile penetration alone.
It is important to remember that female sexual function is a response; it does not occur on its own. Your sexual response also depends on your partner's role and on techniques such as foreplay. If your partner has sexual problems this is also likely to impact on your joint experience.
What are libido and arousal?
This is your overall desire for sexual activity. Women may desire sexual activity because they feel aroused, because they enjoy sex and expect to be aroused, or because their self-image is associated with enjoyable sexual activity. They may also desire to have sex because they wish to please or be intimate with their partner - and libido can therefore be completely separate from physical arousal.
Libido makes you ready and willing to engage in sexual activity. It is a state of mind, allowing the body to focus on sexual stimuli, allowing relaxation and being 'in the moment'. However, it also needs a receptive and willing body, as if you are in discomfort or pain your brain may 'cancel' your desire for sex by reminding you that this may not be pleasurable.
Libido is influenced by hormones, by blood flow to the genital area, by the nervous system and by the brain. It tends to reduce with age when sex hormone levels are reduced, and can be increased by replacing them.
Arousal is the physical sensation of sexual excitement. It is accompanied by physical changes, particularly in blood flow to the genital organs, which become swollen and sensitive (particularly but not only the clitoris), with an increase in vaginal lubrication (however aroused you are, the anus does not have natural sexual lubrication). Other parts of the body are also affected - for example, the nipples may become erect, breathing and heart rate increase, the sensitivity of the skin alters, sense of smell is enhanced, and the brain becomes focused on sexual and emotional stimuli.
Women differ in the stimuli needed to cause arousal, and the physical responses of women's bodies vary hugely. For arousal to take place the right emotional and psychological responses need to be in place, but your body needs to be able to respond physically. This needs an intact blood flow and nerve supply to healthy genital tissues.
What is orgasm?
Orgasm is a variably prolonged sensation caused by a sequence of nerve and muscle actions. It's a powerful feeling of sexual pleasure and release of tension. It results from sudden firing of a particular group of pelvic nerves, usually after a period of arousal and continuing stimulation of the clitoris, vagina, or both. It is accompanied by rhythmic contractions of muscles, including the pelvic floor muscles. For orgasm to occur the nerves which trigger it must be working - but orgasm also requires good blood flow to the genital tissues, an absence of negative distractors such as pain, and the right signals from the brain.
Traditionally, female orgasm was believed to be caused only by the clitoris but it is now known that the vagina and the pelvic floor muscles are also involved in orgasm. Vaginal and clitoral orgasms involve slightly different nerve pathways.
Studies suggest that the most important organ in orgasm is the mind, and the most important external factor is the relationship. The desire to have sex, sexual values, good sexual self-esteem (including the ability to focus on the moment), skills in communication, and your partner’s qualities and sexual techniques are the best promoters of orgasm. Orgasm isn't guaranteed when you begin sexual activity, it depends on positive feedback to the brain from physical and emotional stimuli during sexual activity. In studies of orgasms a relationship that feels good and works well emotionally, where sex is approached openly and appreciatively, is associated with greater orgasmic capacity. In addition, more frequent and long-lasting love-making adds to the chance of learning to achieve orgasm through having sex (intercourse).
Women differ greatly from one another in terms of their tendency and capacity to experience orgasms. In a 2015 survey in Finland, around half of women said that they very often had an orgasm when having sex. Around 4 in every 10 of women had orgasms infrequently or rarely, and nearly 1 in 10 women reported never having had an orgasm from having sex.
Middle-aged and older women seem to have a higher incidence of orgasms than women in younger age groups.
What causes problems with desire and arousal?
Desire and arousal are affected by your body's general health and by the health of your genital tissues, their blood and nerve supply, by hormones and other neurotransmitters, and by the brain. The kind of things which tend to reduce desire and arousal also impact on orgasm (below). They include:
- Emotional factors: for example, relationship difficulties, lack of sexual communication, low expectations of sex, low self-esteem, embarrassment, self-consciousness, inability to relax.
- Lack of experience: shyness and uncertainty about what to expect from sex.
- Psychological factors: for example, anxiety, depression, stress and worry, fear of interruption.
- Practical factors: for example, lack of privacy, lack of experience, lack of partner experience.
- Partner factors: lack of technique, erectile dysfunction, short duration of sex (intercourse).
- Increasing age: after the menopause there can be shrinkage, thinning and reduced sensitivity of the genital tissues, and reduced ability to swell and lubricate.
- Altered hormone levels: oestrogen plays an important role in keeping the genital tissues thicker and more responsive. Testosterone has some role in women's sexual response - although it seems less important than it is in men, and women's testosterone levels are very much lower than those of men.
- Obesity: this can reduce arousal and libido through discomfort and low self-esteem, but possibly also due to the altered hormone balance which results from having a high proportion of body fat.
- Endocrine and hormonal conditions affecting the health and sensitivity of skin and genital tissues: for example, hypothyroidism, hyperthyroidism, liver or kidney disease
- Poor blood flow: this is influenced by anything that reduces blood flow, including increasing age, smoking, some medicines, atherosclerosis, metabolic syndrome and diabetes.
- Reduced vaginal or pelvic floor tone.
- Damage to pelvic or spinal nerves: for example, through surgery, radiotherapy, injury.
- Neurological conditions affecting nerves in the brain, spine or pelvis: for example, multiple sclerosis, Parkinson's disease, stroke.
- Alcohol: although alcohol in brief excess can be disinhibiting (allows you to do things you might not otherwise do, or makes you reckless) and may enhance arousal or orgasm by removing inhibitions which might otherwise prevent them, in the long term alcohol is a depressant substance which impacts on central (brain) arousal and, probably, on tissue sensitivity.
- Smoking: in the long term smoking affects blood flow to all tissues, including the genital area.
- Medication: many medications affect arousal, orgasm or both. Antidepressants are well known to have a powerful effect but the list of medication which can affect you is quite long and includes many hormone medications, blood pressure treatments, medicines used in mental health, sedatives, stronger painkillers, antiepileptic medicines and illicit drugs.
What causes problems with orgasm?
The most important part of orgasm is the brain, which sends signals to the tissues and nerves which put them in a state which makes orgasm possible. However, physical factors are also extremely important. All FSD, including problems with orgasm, is made worse by smoking, poor health, lack of fitness, obesity, cardiovascular disease, poorly controlled diabetes, alcohol, medicines and almost all illicit drugs. These are the same factors that cause erectile problems in men.
It is unusual if not impossible to be able to achieve orgasm without sufficient arousal, but arousal does not guarantee orgasm, as the right stimulus and brain feedback are needed for orgasm to happen. Orgasm also takes time and if the sexual experience ends before the woman reaches orgasm because her partner does so, arousal (and a sense of frustration) may remain for a time. Any of the factors listed above that can interfere with arousal also affect the ability to achieve orgasm. In addition, even if arousal is present, orgasm requires focus, relaxation, concentration and (usually) some active participation. Orgasm is less likely to happen:
- If the brain's ability to experience sexual excitement is interrupted or inhibited - for example:
- If your mood is low.
- If you are very stressed, unhappy, worried or bereaved.
- If you do not feel intimate with your partner.
- If you are feeling unwell, or are in pain.
- If you expect to be interrupted and cannot relax.
- If you are worrying that you won't achieve orgasm and thinking about orgasm rather than focusing on the sex.
- If your partner achieves orgasm and therefore terminates sex before you have reached orgasm. Many women in surveys valued their partner's orgasm above their own. Many allow their partner to believe that they achieve orgasm when they do not, which can worsen the problem, as the partner will feel they have no more to accomplish.
- If you have experienced sexual abuse in the past, this is likely to affect relaxation, letting go and self-image. (Having sex (intercourse) may also trigger memories of abuse.)
- Lack of privacy, distractions or interruptions - for example, babies, children or teenagers in the home.
- Some medicines can specifically prevent orgasm rather than arousal, including antidepressant medications.
- Orgasm is less likely if you don't fully participate physically to enhance your own sexual excitement. Most women who achieve orgasm when having sex help the orgasm happen - through choice of sexual positions, through actively contracting the pelvic muscles, through making adjustments to increase sexual pleasure, and through feeding back to their partner, through words or actions, 'what works'. You are less likely to do this if:
- You are tired.
- You are inexperienced or shy.
- You do not know your partner well.
- You do not believe you can achieve orgasm.
- Multiple physical factors affect the ability to have orgasms. These include:
- Not being sufficiently physically aroused (for example, due to lack of foreplay).
- Reduced ability to tighten the pelvic floor muscles and lower vagina (for example, soon after childbirth or if you never exercise your pelvic floor, leading to low expectations and reduced sexual enjoyment).
- Reduced blood flow to your genital area (for example, because of atherosclerosis, a long history of smoking, or diabetes).
- Damage to the nerves in your pelvis or spine (for example, due to surgery, injury or radiotherapy).
- Hormone deficiencies such as having an underactive thyroid gland (hypothyroidism).
- Increasing age - particularly the lowered hormone levels which occur after the menopause.
- Genital pain.
- Pain in the joints - particularly the hips.
- Clitoral shrinkage after the menopause (sometimes called clitoral insufficiency). The size of the clitoris varies in women and it is not known what influence this has on the ability to orgasm in pre-menopausal women. In postmenopausal women shrinking of the clitoris and vaginal tissues due to lack of oestrogen (and possibly testosterone) reduces sensitivity and, therefore, arousal and orgasm.
Does masturbation help or harm female orgasm?
In the past women experiencing problems with arousal were told that masturbation would help. Masturbation is a normal part of female sexual function, and most women achieve orgasms through masturbation several years before they achieve them through having sex. Masturbation increases awareness of the clitoris and sensitive tissues and may improve the ability to focus on sex and to relax during sex. Although women don't seem to have more frequent orgasms by increasing masturbation, masturbation probably allows the body to 'practise' orgasm, so that you are better at focusing on the sensations that lead to it.
The ease of reaching orgasm via masturbation is not a good measure of ability to achieve orgasm whilst having sex, but orgasm through masturbation does not prevent orgasm through having sex. However, very frequent masturbation (particularly with sex toys, which can be highly stimulating) may actually reduce the chance of orgasm whilst having sex - by over-stimulating the clitoris and making it less sensitive. Women who use vibrators repeatedly have reported 'buzzing' sensations from the clitoris which are probably caused by inflammation and over-stimulation. These settle after a period of restraint. It is possible to bruise or injure the clitoris through vigorous use of sex toys, leading to hypersensitivity and soreness, but again this usually settles after refraining for a few days.
What is genito-pelvic pain/penetration disorder?
This rather lengthy term means you regularly experience difficulty in vaginal penetration, marked vulvovaginal or pelvic pain during penetration, fear or anxiety about pain when preparing for, during, or after penetration, or tightening/tensing of pelvic floor muscles during attempted penetration (this is also called vaginismus).
Pain in the course of having sex (intercourse) is generally referred to as dyspareunia. It can be positional, or occur in all positions; it may be partner-related or technique-related; it may occur only in certain situations (for example, when using condoms) or in all situations, and it may come and go over time, or be there every time you attempt to have sex.
What causes genito-pelvic pain/penetration disorder?
Pain associated with sex (intercourse) can have many causes, both physical, psychological and situational. If you experience pain on having sex then this is likely to affect both arousal and orgasm, and may also affect libido.
Causes of pain during sex include all the causes of poor arousal above, and conditions which directly cause increased pain in the pelvic area.
- Lack of intact, lubricated tissue - for example, vaginal dryness due to insufficient arousal, thinning and increased fragility of the vaginal tissues with age or hormone deficiency.
- Reduced blood flow to the tissues - for example, peripheral arterial disease, atherosclerosis, diabetes, smoking, low oestrogen levels, some medicines.
- Soreness and irritation due to infection (for example, thrush) or condom allergy.
- Scarring - for example, from stitches after childbirth.
- Fear and anticipation of pain leading to tight contraction of the pelvic floor muscles when attempting to have sex (a condition known as vaginismus): this can date from a very first experience of having sex, or can develop later, and can prevent intercourse entirely.
- Gynaecological conditions including prolapse, endometriosis, adenomyosis, fibroids, pelvic inflammatory disease, ovarian cysts and gynaecological cancers.
- Pregnancy can lead to vaginal dryness and therefore pain, together with physical discomfort due to conditions like pubic symphysis separation, morning sickness and the bulk of the enlarging womb (uterus). Some women also complain of vaginal dryness whilst breast-feeding.
- Partner technique - this can be particularly difficult if your partner is relatively large and you are relatively small.
- Non-standard sexual practices for which your body is not adequately prepared or lubricated (for example, sex toys, anal sex).
Pain on having sex may also relate to conditions elsewhere in the body - for instance, bowel conditions such as irritable bowel syndrome (IBS) and Crohn's disease may cause pain on having sex. Joint pain may make having sex painful, particularly if it affects the hips. Generalised pain (such as in fibromyalgia) or chronic pain reduces libido and arousal and orgasm.
What will my doctor want to know if I have female sexual dysfunction?
Your doctor will want to assess your problem and how it impacts on you, and will want also to get an idea of what you expect from having sex and what is normal for you. This means that some of the discussion and questions in your consultation may seem very personal.
Your doctor will want to identify which type or types of FSD you are experiencing. If you experience pain it may be helpful to describe exactly when, during penetration, you feel the pain, and where. The doctor may ask if you think lack of foreplay, short or long duration of sex, particular positions, condoms, or sexual problems in your partner could be a factor. They may also ask whether you feel difficulties in your relationship could be showing themselves in your sex life, and whether you have a lower sex drive or less sexual enjoyment than in the past. They will ask about alcohol, smoking and any medicines or drugs you are taking (ether on prescription or otherwise).
Your doctor will want to know if you have been experiencing any mental health issues such as anxiety, depression, post-traumatic stress disorder, or eating disorder (which can affect your body image and your hormone levels). They will want to know whether you can think of anything that could have affected your sexual enjoyment.
The doctor will suggest checking for physical causes which might be contributing to FSD. This will involve talking about your general health and fitness, and examining your heart, lungs and blood pressure. Examination of your pelvic area, possibly including internal examination and swabs, may be helpful, particularly if you have pain.
Blood tests are often done to look for some of the hormonal and endocrine conditions which can lead to FSD. These include checks for thyroid disease, diabetes and hyperlipidaemia, and checks of your hormone levels.
How is female sexual dysfunction treated?
Treatment will depend on the underlying reasons for the FSD. There will often be several, as once something interferes with sexual response then feelings, anxieties and a sense of low expectation can quickly be added.
In the past FSD was mainly treated with psychosexual therapy, sometimes with relationship counselling. However, we now understand that there are often physical contributors to FSD, and many of these can be treated.
What treatments for female sexual dysfunction don't involve taking medicines?
Improved health and well-being and general fitness, stopping smoking and keeping alcohol consumption below the recommended limit all help with FSD. If you are overweight or obese then weight loss can make a big difference.
Couple counselling and psychosexual counselling
Where issues in your relationship or you and your partner's differing sexual expectations form a part of the FSD, counselling or psychosexual counselling can be very helpful.
Cognitive behavioural therapy and psychotherapy
Psychotherapy may help remove inhibitions and help libido and arousal - and therefore orgasm. Cognitive behavioural therapy (CBT) in women with vaginismus leads to improvements. FSD associated with chronic pain can be improved by adding CBT to pain treatment.
Pelvic floor exercises
Your pelvic floor plays an important part in arousal and orgasm. Regular pelvic floor exercises can produce improvements in desire, arousal, lubrication, orgasm and satisfaction with sex. This is true of all FSD, but particularly effective in FSD experienced after childbirth.
The Eros Clitoral Therapy Device is a handheld medical device approved in the USA for sexual arousal and orgasmic disorders in women. It can help some women who have difficulties with arousal, particularly when used during foreplay and having sex.
What medicines help with female sexual dysfunction?
There is no licensed medication specifically for FSD in the UK (although flibanserin is now licensed for FSD in the USA). Any prescribed medication for FSD is therefore 'off-label'. In practical terms this means that whilst the drug has been tested and proved to be of benefit for other conditions (or, in the case of testosterone, for men with testosterone deficiency) it has not been licensed for FSD, and this usually means that either the manufacturers have not felt the need to apply for a licence, or that they do not think they have enough evidence to get one if they were to try.
Many medicines are prescribed 'off-label' in the UK, but if prescribing to you 'off-label', doctors must explain the pros and cons of you taking the particular medicine - and be sure you understand and are clear that you want to go ahead.
Oestrogens are commonly used for the treatment of FSD around and after the menopause, when natural oestrogen levels fall. Oestrogen is available as oral tablets, dermal patches, vaginal pessaries, implants, creams and jellies. Oestrogen improves sexual pain, desire, arousal, sensitivity, lubrication and orgasm. Whilst oestrogen is not licensed to treat FSD, if is licensed for treatment of menopausal symptoms in women.
Tibolone is a steroid used (and licensed) for the treatment of menopausal symptoms. It improves desire and overall sexual function in postmenopausal women.
Testosterone is one of the most frequently prescribed ('off-label') medications for women with sexual interest/arousal disorder. However, the role this hormone plays in normal, healthy women is not clear. Women do have circulating levels of testosterone but they are very much lower (about a tenth as much) than those in men. Testosterone levels in women decrease with age (particularly after the menopause) but it is not known what level of testosterone in a woman is 'too low', and testosterone levels are hard to assess with blood tests as they can vary throughout the day.
In pre-menopausal women, treatment with testosterone only seems to improve FSD in high doses which, over time, may result in excess hair growth, deepening of voice, and hair loss.
In postmenopausal women with decreased desire, the addition of testosterone to oestrogen does help FSD, increasing libido, arousal, clitoral sensitivity and orgasm.
Testosterone is therefore normally offered only to women who have a reason to have lowered testosterone levels, such as menopause. If you are given testosterone treatment your testosterone levels will need to be monitored to make sure you are not overdosed. Testosterone is usually used as patches, gels or creams, and occasionally as an implant.
Flibanserin is licensed in the USA for the treatment of FSD, although this has been controversial. It has been called 'women's Viagra®' but in fact it acts on the brain (whilst Viagra® acts directly on the blood flow to the penis). Flibanserin acts on the thinking and emotional area of the brain, where it alters the balance of neurotransmitter chemicals towards sexual excitement, and away from inhibition.
The manufacturers state that this results in increased frequency of satisfying sexual events and in intensity of sexual desire. The evidence is not strong and points to, if anything, a small increase in sexual activity in women taking flibanserin. It can cause dizziness, somnolence, nausea and fatigue, and cannot be taken with alcohol or grapefruit juice.
Viagra® and phosphodiesterase type 5 inhibitors
The introduction of the 'blue pill' revolutionised the treatment of erectile problems in men, but sildenafil (Viagra®) and the other phosphodiesterase type 5 inhibitors (PDE-5 inhibitors), are not licensed for use in women. PDE-5 inhibitors increase genital blood flow to the penis and there is increasing evidence that they have the same effect on the clitoris and genital area. Although the clitoris does not become erect by quite the same mechanism as the penis, sildenafil does seem to improve both arousal and orgasm. It is likely that research will continue and that these medicines will eventually be licensed for use in FSD.
Currently, any prescription is 'off-label'. Side-effects include headache, flushing and changes in vision, and these are common. These medicines cannot be taken if you are on nitrate tablets for heart disease.
Bupropion is best known as an anti-smoking medicine. It helps FSD in women whose FSD is caused by taking antidepressants. These women are otherwise in a 'catch 22' situation - as untreated depression will also reduce their sexual function.
Phentolamine and yohimbine
These are occasionally used to treat FSD, with the aim of increasing genital blood flow and therefore arousal. Phentolamine does seem to improve arousal, but there is no good evidence for yohimbine in improving FSD. Despite this, yohimbine (available as a food supplement) is widely marketed as a sexual performance enhancer.
A few other medicines may have a role in treating FSD. Promising substances include:
- Alprostadil (a cream applied to the genital area which seems to increase blood flow and, therefore, arousal).
- ArginMax® (a nutritional supplement containing extracts from ginseng, ginkgo, damamiana, and L-arginine, with various vitamins and minerals), which may do the same.
FSD is common and can have many different, interacting causes. Ageing, physical illness and emotional factors can all play a large part. Lack of fitness, obesity, cardiovascular disease, diabetes and (in older women) low hormone levels play significant parts.
Treatment depends on the main causes. Talking therapies and relationship counselling can be very helpful. Hormone treatments are helpful after the menopause, or if there is a proven hormone deficiency. The PDE-5 inhibitors such as sildenafil (Viagra®) and alprostadil cream may be licensed in the future and do appear to be helpful in cases of low arousability or reduced orgasm at all ages. At present, no medicines are licensed in the UK for the treatment of FSD.
Further reading and references
; Managing female sexual dysfunction. Fertil Steril. 2013 Oct100(4):905-15. doi: 10.1016/j.fertnstert.2013.08.026.
; The role of pelvic floor muscle exercise in the treatment of female sexual dysfunction, Journal of the Association of Chartered Physiotherapists in Women’s Health, Autumn 2014, 115, 22–29
; Journal of Marital and Sex Therapy: 2000: 26:191-208
; Determinants of female sexual orgasms. Socioaffect Neurosci Psychol. 2016 Oct 256:31624. doi: 10.3402/snp.v6.31624. eCollection 2016.