Dear Readers: In last week’s column, we heard from a woman who, was planning to get pregnant. We talked about a number of important steps she should take before actively trying to conceive. Even though she’s the one who’ll be carrying the baby, there’s plenty that the dad-to-be can do to increase fertility and up the odds of a healthy pregnancy.

So dad–your goal is to prepare a healthy environment for the baby to swim around in, and to prevent birth defects or other complications, right? But you never know when your partner is going to burst out of the bathroom waving a little white stick, and announce, “Honey, I’m pregnant!”

So let’s start by making an appointment to see your doctor. Give him your medical history and tell him about your plans to do the dad thing. You need to know whether there are any issues you should address before you start planning those romantic, candlelit, birth-control-free evenings. One especially important topic to discuss is how to make sure your sperm is healthy. Here are some ways to do that:

  • Be cool. Sperm is very sensitive to heat, which is why your testicles—where those little swimmers of yours live—hang outside your body, where it’s cooler. Heating them up by a couple of degrees (say, by spending any more than five minutes in a hot tub or bath, sitting with your legs crossed for extended periods of time, or wearing tight underwear that keep your testicles up against your body) could reduce sperm production or cause abnormalities. We all know that women have fertility cycles, but did you know that men do too? Turns out that sperm are on a 90-day cycle, meaning whatever happens to them today won’t show up for about three months.
  • Call in the vice squad. Smoking, using illegal drugs (or misusing legal ones), and drinking alcohol have all been linked to lowered fertility, miscarriage, and birth defects.
  • Watch the toxins. Hazardous chemicals, pesticides, and even noxious fumes could damage sperm and, if you inadvertently bring them home (like on your clothes), they could hurt your partner too.
  • Lose some weight. Dr. A Ghiyath Shayeb, from the University of Aberdeen, Scotland, found that obese men produce lower volumes of seminal fluid (the liquid that carries the sperm) and have a higher proportion of abnormal sperm. “[m]en who are trying for a baby with their partners, should first try to achieve an ideal body weight,” says Shayeb.
  • Start taking a vitamin supplement. Several fertility specialists I interviewed mentioned that there’s growing evidence that sperm production requires Folic Acid, vitamin C, L-Carnitine, Coenzyme-Q, and other nutrients. No guarantees, but taking these supplements (with your doctor’s approval, of course) may make your boys go from mediocre to Michael Phelps.
  • Have a little more fun. Traditional thinking has it that if you want to improve your chances of getting your partner pregnant, you shouldn’t ejaculate for at least a couple of days before trying. But Australian OB David Greening disagrees. Greening studied men with DNA-damaged sperm. After seven days of ejaculating daily (no, it didn’t matter how they got there), the percentage of damaged sperm dropped significantly. And motility—a measure of how straight and how quickly sperm swim towards those ever-elusive eggs—increased.

Aside from all that, spend some time talking with other guys about what it’s like to be a dad, the challenges they face, and how they overcame them. You can learn a ton from other people’s experiences.