Still believe certain positions boost your baby-making chances? How women continue to hold misconceptions about female biology The basics of baby-making are important both for women who want to conceive, and those who want to avoid getting pregnant. But according to a new study published today in the journal Fertility & Sterility, 50per cent of U.S. women incorrectly believe that having sex more than once per day will increase their chances of conceiving. Similarly, one-third believed that certain positions during intercourse would also boost their chances. According to a new study published today in the journal Fertility & Sterility, 50per cent of U.S. women incorrectly believe that having sex more than once per day will increase their chances of conceiving The web-based study surveyed 1,000 women ages 18 to 40 from across the U.S. -- 80per cent of whom said they were currently sexually active. Nearly 20per cent of women are unaware of the negative effect aging, and obesity, has on reproduction; while 30per cent of American women are oblivious to the impact a sexually transmitted infection has on their fertility. And 40per cent, who falsely believe that women continue to make new eggs as they age, also do not know that ovulation occurs 14 days before the next period. 'This was a highly concerning finding, that in a country such as United States, and in a population which is Internet savvy, a significant proportion of women are really not aware of the basics,' said study researcher Dr. Lubna Pal, associate professor of Obstetrics, Gynecology, and Reproductive Sciences at Yale University. Designed to gauge participants' knowledge of female biology through 'false' or 'true' questions, the survey also revealed that about half of women had never discussed their reproductive health with a medical provider. 'These are mis-perceptions, and really for an educated public with such easy access to correct information, there's no room for such errors to be lingering around in our perceptions,' explained Dr. Pal. Twenty-three per cent of women in the study who were not planning on becoming pregnant were not using any form of birth control. Of the 77per cent on birth control, 18per cent were using condoms and 38per cent reported using a hormonal method.