Whether or not you have siblings--and whether they were born before or after you--goes a long way toward determining what kind of person you are.

About 80 percent of you have at least one brother or sister, and science says their influence goes way beyond whether or not you had someone to play catch with or just had to silently bounce a ball off the garage door in the driveway.

5 Older Brothers Can Turn You Gay (Seriously)

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Guys, remember the torment that your older brothers put you through when you were growing up? If you are the oldest (or only) brother in your clan, then you're lucky. You didn't have a bunch of quarterbacks pulling your arms behind your back, stealing your glasses and calling you a pencil-necked little gaynerd.



Plus, your younger brothers provided ample punching practice.

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If your mother spat out a few boys already before you came along, then you know the pain of having your older brothers constantly questioning your sexuality. You may be interested to learn that, according to science, they were right to do so: Having older brothers increases the probability that you will be gay.

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It's called the Fraternal Birth-Order Effect, and it's quite clearly documented. For each son a woman produces, the chances that the next one will be spending his first 20 years inside a closet increase by 28 to 48 percent. By the fourth or fifth, you might begin to notice a puzzling affinity for musical theater.

Now, keep in mind the base rate of homosexuality is low already, you would need over 10 brothers before your probability of being gay propelled over 50 percent. Still, it's estimated that one in seven gay men can attribute their sexuality to this effect.