The big moment has arrived and you're actually having sex. In addition to all of the fun, your bodies are building up tension that you hope will end in orgasm, that wonderful, pleasurable release that also has an important biological function. In men, orgasm propels sperm-rich semen into the vagina and up against the cervix at roughly 10 miles per hour. This process, known as ejaculation, gives sperm a head start on their way to the egg. A woman's climax also aids conception. Some research shows that the wavelike contractions associated with the female O help pull the sperm farther into the cervix. So what's the take-home — or take-to-bed — message? Let go and have as much fun as you can. It can only help your chances of getting pregnant.Many couples wonder if a particular sexual position is best for baby-making. No one knows for sure, but some experts believe the missionary position (man on top) or the rear-entry position (man behind woman, both facing the same direction) are best because they allow for deep penetration. But do whatever you like. The most important thing about sex is that you're both having a good time and you're doing it frequently enough that live sperm are in the woman's reproductive tract during ovulation. That means you should aim to make love at least every other day during the middle of your cycle. During the afterglow, sperm fight to the finish
If conception is going to happen, it will be in the first few hours after sex. At this point, you can't do much except cross your fingers and hope, though some experts say the woman should stay on her back, with a pillow under her butt, for at least 20 or 30 minutes so gravity can help the sperm get to the waiting egg.
While you and your partner are enjoying a relaxing post-romp cuddle, a great deal of activity is taking place inside your body. Those millions of sperm have begun their quest to find your egg, and it's not an easy journey. The first obstacle is the acid level in your vagina, which can be deadly to sperm. Then there's your cervical mucus, which can seem like an impenetrable net except on the one or two days when you're most fertile and it miraculously loosens up so a few of the strongest swimmers can get through. But that's not all — the sperm that survive still have a long road ahead. In all, they need to travel about seven inches from the cervix through the uterus to the fallopian tubes. When you consider that they travel at a rate of roughly an inch every 15 minutes, that's quite a trip. The fastest swimmers may find the egg in as little as 45 minutes, while the slowest can take up to 12 hours. If they don't find an egg in the fallopian tubes at the time of intercourse, the sperm can wait there in a resting stage for up to 72 hours.