What Is the O+12 Method?

Can I really boost my chances of conceiving a girl through the O+12 method? How does it work?
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ByPeter G. McGovern, MD, director, Division of Reproductive Endocrinology and Infertility, University of Medicine and Dentistry of New Jersey, Newark; medical director of University Reproductive Associates, Montclair, NJ
Fertility Specialist
Jan 2017
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Always dreamed of having a little girl? There’s a system in place that might up your chances beyond the 50/50 mark. Known as O plus 12, it stands for “Ovulation plus 12 hours.” That’s about the time, according to believers, when you should get busy. There is some nugget of science behind the theory, which holds that eggs are more likely to admit an x-containing sperm (the kind you need to have a girl) if they are fertilized about 12 hours after ovulation.

The difficulty comes in determining just when your egg pops out of the ovary. It’s almost impossible to accurately calculate your ovulation down to the very hour that it occurs, and even some of the more popular methods (body temperature, cervical mucus, ovulation prediction kits) are highly inaccurate. (To say nothing about the pressure you may be putting on your partner to perform at that very moment.) If you’re intent on having a girl and want to give it a try, have fun, but just remember your odds of having a boy or girl are generally the same no matter what time of day you decide to make a baby.


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