There is an overwhelming lack of understanding when it comes to  female sexuality, from orgasm to dysfunction and general likes and  dislikes, than there is for men. Just last week, researchers from Yale  University were able to explain an evolutionary idea that attributes a woman’s orgasm to ovulation. While the two may have once been linked, mammals evolved menstrual cycles  — and now they no longer need the hormonal rush of an orgasm to  ovulate. Good thing, too, since only 57 percent of women in a 2015  survey reported achieving orgasm most or every time they had sex, Mic reported. For anyone who thinks that’s actually pretty good, their male partners had orgasms 95 percent of the time.

Part of the problem is that science and research fields are still dominated by men;  it’s not a coincidence we know more about the penis than the clitoris.  There’s also poor knowledge of female anatomy among both men and women,  and as Mic put it, “better knowledge of the parts can help with the mechanics.”

Lucky for you, we rounded up sex facts that (ahem) touch on knowledge and mechanics.

1. Vaginal orgasm is really an internal clitoral orgasm

The sole purpose of a woman’s clitoris is to provide pleasure, and  that’s it. Approximately 8,000 sensory nerve fibers are located in the  “tender buttons” (for you Gertrude Stein fans) or “bulb” beneath the  clitoral hood, nearly twice the amount found on the head of a penis. But  there’s literally more: The clitoris is mostly subterranean,  which means it mostly exists inside the vagina. The circular mass on  the outside is connected to the shaft of the internal clitoris, and  stimulating that shaft with either a penis or sex toy can greatly  increase stimulation.

2. Women think about and want frequent sex, too

The idea that men are the only ones who think about sex all day is  more stereotype than fact, (and that it’s as often as every 7 seconds is  not proven by science). A recent survey  from fertility app Kindara found that 53 percent of women were not  having sex as much as they would have liked. In fact, almost three  quarters of respondents wished they had sex at least three times a week.

3. Horny women were once thought mentally ill

Women living in the 19th century were considered crazy  for having sexual urges. Physician George Taylor called it hysteria, a  mental disorder that included symptoms like “excessive vaginal  lubcrication” and “erotic fantasy,” The Huffington Post reported. Shocker, then, that it could be cured by "pelvic massage."

4. Female sexuality is much more fluid

In 2016, a study published in the Journal of Personality and Social Psychology  found that women were equally turned on by men and women, going so far  as to say they could only be gay or bisexual, not straight. It’s not a  generalizable study, but it echoes an earlier study  that suggested women evolved to be more fluid than men as a mechanism  to reduce conflict and tension among wives in polygynous marriages.

5. Period sex is not off limits

Period sex  has been a trending topic for years; all that’s changed recently is the  number of men and women openly talking about it. Some can’t get behind  it, but others enjoy the increased arousal and lubrication during that  time of the month. Since the body is essentially preparing for  reproduction, women sometimes feel more sexual during these encounters.

6. Penis size doesn’t always matter

Small studies on the relevance of a man’s penis size  to women suggests it matters — but a 2015 video from Cut.com, a website  devoted to video content, showed more women disagreeing with this idea  than anything else. For many of them it mattered more “how you use it.”  And then there is research, too, that shows men worry more about size than women.

7. Missionary is best for women with back pain

More than half of American adults deal with some kind of back pain, and in a study  from Waterloo University, researchers found missionary position while  using a pillow for back support was best. For women feeling pain when  touching their toes or after sitting for long periods of time,  researchers recommended spooning or the doggy-style position

8. Personality plays a role

In a study  of 278 newlywed heterosexual couples married for six months or less,  researchers found both husbands and wives with low levels of neuroticism  reported being more satisfied with their sex lives. Then, a study published in the Journal of Research in Personality  found women who felt pressure from a partner to be perfect worried more  about their sexual performance, possibly increasing the risk for sexual  dysfunction and anxiety.

9. Apples an aphrodisiac?

An Italian study  found that women who ate more apples experienced increased lubrication  and sexual function, increasing their overall libido. As Medical Daily previously reported,  the researchers believed the link had to do phloridzin, a key compound  in apples that “mimics the female sex hormone estradiol, which plays a  huge role in vaginal lubrication and female sexuality.” You can learn  more about potential aphrodisiacs, and if they even work, here.

10. Infertility impacts 1 in 8 women

Even researchers of a recent study  were surprised to find that almost half of the people experiencing  infertility had not sought help. This can negatively affect women’s  well-being, possibly leading to depression and emotional distress.