Historically research has focused on men. As one example, women are under-represented in major clinical trials for cancers that affect both sexes, a new study found. Researchers say several factors could be responsible, from childcare issues to reluctance by researchers to expose women of childbearing age to trial drugs and treatments.

    In other areas where research into women's medical problems is lacking, the issue is not just about sexism. Women's hormone fluctuations are, well, complicated and can confound basic findings. But in recent years, women have been getting increased attention.

    Still, much misinformation about the female body circulates in mainstream consciousness.

    Myth: A women can't get pregnant during her period.

    While a woman is unlikely to conceive during menstruation, "nothing, when it comes to pregnancy, is impossible," said Aaron Carroll of Indiana University and co-author of "Don't Swallow Your Gum: Myths, Half-truths and Outright Lies About Your Body and Health" （St. Martin's Griffin, 2009）. Once inside a woman, sperm can wait for an egg for up to a week. Ovulation can occur soon after, or even during, the bleeding phase of a woman's menstrual cycle, giving patient sperm the chance to get lucky. The timing method of birth control doesn't work well, Carroll said, agreeing that couples who practice it are often called: parents.

    Myth: Menopause causes sex drive to nosedive.

    The Change is not necessarily one that happens in the bedroom. A comprehensive survey of sexual habits in the United States, completed by Edward Laumann and colleagues in 1994, found that roughly half of women in their fifties have sex several times a month. While hot flashes and other discomforts may make a women temporarily not in the mood, there is not a direct link between menopause and sexual desire, Vreeman said. So if you are entering the Big M, there is no reason to say good-bye to the Big O.

    Myth: Antibiotics make birth control pills unreliable.

    "Many physicians even believe this," Carroll said. Alone, birth control pills fail about one percent of the time. And that failure rate is unchanged when taken with the vast majority of antibiotics, Carroll said. A possible exception is rifampin, the antibiotic prescribed for tuberculosis. Rifampin does lower pregnancy-protecting hormone levels induced by birth control pills, but whether the effect is large enough to increase pregnancy risk is unclear. Carroll thinks rifampin research spurred the antibiotic/birth control rumor. "Sometimes people say things and they just take off," he said.

    Myth: Women and men need equal sleep.

    Tossing and turning not only causes women more psychological distress, it also raises their insulin and inflammation levels -- risk factors for compromised health, found a 2008 study of 210 people led by Edward Suarez at Duke University. A study of more than 6,000 participants, led by researchers at the University of Warwick in 2007, found that women who slept five or less hours a night were twice as likely to suffer from hypertension than women who slept for seven or more hours. Among men, there was no such relationship. Sleeping Beauty may be better off waking up on her own watch.

    Myth: A doctor can tell if a woman is a virgin.

    Even when using 10-fold magnification, doctors can not accurately sort virgins from the sexually-active, several studies have reported. It is not as simple as looking for a hole in the hymen because, well, there is always a hole in the hymen. "Some people think the hymen seals off the vagina [until virginity is lost], but that is just not true," said Dr. Rachel Vreeman of Indiana University and Carroll's co-author of "Don't Swallow Your Gum." In the rare cases when it is sealed, period blood builds in the uterus and causes severe medical problems, she said.

    一直以來，大多數研究都把目光放在男性身上。比方說，在那些男人和女人都會得的癌癥研究中，對于女性被試者比男性少很多。研究人員認為這是由多種因素造成的，比如由于婦女需要養育子女，因此很多研究者對讓育齡婦女參加臨床試驗而有所顧慮。

    另一些嚴重對女性健康問題研究的匱乏，就不單單是因為性別歧視了。女性的荷爾蒙作用，比男性更復雜，而且會和基本研究問題產生相互作用。不過近些年，女性正在獲得越來越多的關注。

    不過在我們的視野中，還有很多關于女性健康的錯誤觀點在不斷流傳。

    誤區：女性在來月經時不會懷孕

    雖然女性來月經時的確不容易受孕，"不過在懷孕的問題上，沒有什么是不可能的。"印第安納州大學的Aaron Carroll曾經這么說過。她曾與人合寫了《別咽口香糖：關于身體和健康真真假假那些事》

    精子可以在女性體內存活長達一周。而排卵可以發生在月經周期剛結束、甚至還在流血的日子里，這讓那些耐心的精子獲得了機會。安全期避孕法并不可靠，Carroll說。她還給那些用這種方法避孕的夫妻們起了個名字：父母。

    誤區：更年期讓"性趣指數"暴跌

    這個變化不一定會發生在臥室里。1994年，Edward Laumann和同事們在美國進行的一項關于性習慣的詳盡調查，調查顯示，在五十多歲的女性中，大約一半每個月仍然會做幾次愛。

    雖然燥熱和其他的不適癥狀會讓女人們暫時"不在狀態",不過更年期和"性趣"之間沒有直接聯系，Vreeman說。所以，如果你到了這個時候，可不意味這你就要想"飄然欲仙"說byebye.

    誤區：抗生素會讓避孕藥失效

    "甚至很多家庭醫生都相信有這么回事"Carroll說。如果只用避孕藥，失敗率是1%,這個比例不會隨著服用絕大部分的抗生素而有所變化。

    一種可能的例外是利福平，一種治療肺結核的抗生素。利福平的確會讓由于避孕藥而產生的避免懷孕荷爾蒙水平降低，不過這個效果能否增加懷孕的危險并不清楚。Carroll認為正是對利福平的研究導致了關于抗生素和避孕藥之間的流言，"有時候人們會說些自己都不清楚的事情".

    誤區：女人和男人需要等量的睡眠。

    根據杜克大學Edward Suarez2008年對210人進行的調查，輾轉反側不但會造成女人心理上的壓力，還會提高胰島素水平和炎癥癥狀，從而危害健康。

    而在另一項2007年Warwick大學研究人員對超多6000人進行的研究，那些睡眠少于每晚5小時的女性比睡超過7小時的女性，罹患高血壓的幾率高一倍。而在男性中卻沒有這種關系。睡美人最好是自然醒。

    誤區：醫生能分辨處女

    不少研究證明，即使用10倍的放大鏡，醫生也不能準確地區分處女和非處女。這并不是看處女膜有沒有洞那么簡單，實際上，處女膜就是有個洞。

    "有些人認為處女膜封上了陰道（直到失去貞操）,不過并不是那樣。"《別咽口香糖》的另一位作者，印第安納大學的Rachel Vreeman介紹說，在極少個案中，它的確是全封閉的，導致經血在子宮中淤積，這會導致嚴重的疾病。