Washington, December 20 (ANI): As 2009 comes to an end, a list of sex lessons that may come handy in the New Year has been unveiled.

Live Science lists the nine main things to remember:

1. Sex smells: A study in The Journal of Neuroscience claims that man’s sweat smells different when he’s sexually aroused.

2. Pulling out works: Withdrawal has been found to be “almost as effective as the male condom” when it comes to pregnancy prevention, a paper published in the June issue of Conception magazine noted.

3. Child’s play: An Iowa State University study has found that 25 percent of children, between 11 and 16, in low-income households reported having sex. The average age of first intercourse for that group was 12.77.

4. Growing pains: Penis extenders may be useful in increasing flaccid members’ length by almost one inch, a study from the University of Turin suggests.

5. The pursuit of pleasure: Men between 20s and 30s and especially those who masturbate frequently are at higher risk for prostate cancer, researchers at the University of Nottingham claim.

6. Pill popping: Birth-control pills are occasionally promoted as a medicine for acne and PMS. The Federal Drug Administration had mandated that Bayer, the manufacturer of Yaz birth-control pills, change their commercials, which made similar suggestions.

7. This is a test: In order to be on the safer side against cervical cancer women should wait until age 21 to get their first Pap smear, get a check-up done every three years, the American College of Obstetricians and Gynecologists have advised.

8. Not yet: Women who hold out on sex are acting on a biological impulse to find more suitable providers, while men are waiting to prove that they’re up to the challenge, research published in the Journal of Theoretical Biology reads.

9. Role reversal: Men apparently feel guiltier following sexual infidelity, while women feel worse after an emotional transgression.

Researcher Maryanne Fisher, a professor at St. Mary’s University in Halifax, Canada, said: “If an individual assumes that everyone, regardless of their sex, is most concerned with the same form of infidelity that they themselves are most concerned about, this person would consequently make false inferences leading to feelings of guilt.” (ANI)