When you're trying to conceive (or trying not to!), you probably think about your cycle or how often you have sex as thing that typically affect your shot at getting pregnant. But there are also some far less obvious factors that influence both your and his fertility.
While this is a laundry list, what really matters most, according to women's health expert Jennifer Wider, M.D., is when you're ovulating, your age (and his as well, at least to up your chances of a healthy baby), your smoking habits, and his sperm count. (In other words, take most with a grain of salt, since by and large the effects are pretty negligible).
But, if you're really trying to optimize your chances, these little things might also make an impact.
1. How much TV he watches
Weird but true: Guys who watch five hours of TV or more per day have a lower sperm count than guys who don't watch TV at all, according to a study in the American Journal of Epidemiology.
2. How stressed you are
This one is actually pretty major. A study in the Annals of Epidemiology found that women who reported above-average stress levels were 45 percent less likely to conceive.
3. What he looks like
Weird but true: guys with a more masculine look (measured by things like face width) tend to have lower sperm quality, one study in the Journal of Evolutionary Biology found.
4. His intelligence
Higher IQs usually correlate with higher sperm quality, according to research from Kings College in London. Score for the smart guys!
5. The timing of your romps
Obviously, the more you have sex, the more likely you are to get pregnant. But interestingly, how far apart you space the sessions matters. The chances of artificial insemination working almost triples when using the second sperm sample collected within an hour, says one study presented at the European Society of Human Reproduction and Embryology meeting.
6. His exposure to hot water
If you've been hanging out in a hot tub, your chances of conceiving may not be great. The sperm count of men in a study in the Brazilian Society of Urology journal increased after they avoided hot baths and jacuzzis for three to six months.
7. The cleaning chemicals in your house
Pesticides, pollutants, and other chemicals can decrease your chances of getting pregnant by up to 29 percent, according to one study in Environmental Health Perspectives. Both men's and women's exposure mattered. The authors think these substances could be affecting our hormone levels.
8. His laptop usage
Apparently, by putting a computer on his lap, he can disrupt what's underneath it. A Fertility and Sterility study examined sperm samples placed underneath laptops, and 25 percent of the sperm stopped swimming, while only 14 percent of sperm placed safely away from laptops did. Time for an iPad?
9. Which birth control you've taken in the past
Obviously, taking birth control right before you're trying to conceive can (and uh, should) reduce your chances of getting knocked up. But if you've taken Depo-Provera, that effect could last for up to two years. If you're taking the shot and you want kids in the semi-near future, you should start thinking about going off it now.
10. Whether you're breastfeeding
Kind of a handy trick: most moms don't ovulate with they're breastfeeding, so your chances of conceiving one baby while you're nursing another are quite low, though not zero.
11. What kind of underwear he wears
This is a personal favorite: Sperm grow best under temperatures lower than the rest of the body, and when his balls are squished into tight undies, let's just say things can heat up in there. If he's trying to maximize his sperm count, the answer to the "boxers vs. briefs" question is a no-brainer: boxers.
This article originally appeared on Glamour.