Making babies: a quick biology review

Trying to conceive? It seems like a simple equation: sperm plus egg equals baby. But it's not always as easy as it sounds. A variety of events must occur in just the right order to produce a pregnancy. Here's a quick review of baby-making biology.

The female side of the "equation"

In order to conceive, a woman must release an egg that can then be fertilized by the man's sperm. A woman's menstrual cycle is generally 28 days long, although some women have cycles that are longer or shorter than this. Day 1 is the first day of a woman's period. Sometime around Day 14 (for women with a 28-day cycle), she releases an egg from her ovaries – this is called ovulation. The egg travels down the fallopian tubes into her uterus, where it can then be fertilized. The process of ovulation is regulated by female hormones.

The male side of the "equation"

To father a child, a man must produce sufficient amounts of healthy sperm. Sperm are produced in a man's testes, pass through the epididymis, and are stored in the seminal vesicles.

The man must be able to deposit his sperm into the woman's vagina during intercourse. This usually happens during ejaculation. Then, the sperm must be able to swim well enough to reach the egg.

Sperm, meet egg.

To produce a pregnancy, the woman's egg must be fertilized by the man's sperm. The fertilized egg must then implant into the wall of her uterus, where it can begin to grow.

The secret to conceiving is proper timing. A woman's egg can live for up to 24 hours after it has been released. Sperm can survive inside a woman's body for a few days, and sometimes as long as 3 to 5 days. So, to maximize the chances of pregnancy, it is important to have intercourse around the time of ovulation (when the egg is released).

Women can calculate their ovulation time by tracking their menstrual periods. Ovulation usually occurs about 12 to 16 days before a woman's next period is expected. This method works best for women with regular cycles. But there are also other methods, including monitoring body temperature (which rises around the time of ovulation) and cervical mucus (which develops a slippery egg-white consistency around ovulation). Women can also use fertility monitors and ovulation kits to pinpoint the time of ovulation.

If you have any questions or concerns about fertility, speak to your doctor.

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