When's the Best Time to Start a Family?

Reality: Physical size and strength do not correlate to sperm count. A "male factor" is involved in as many as 50 percent of infertility cases—odds which justify the brief embarrassment of producing the sperm sample. (Fertility clinics have private rooms with pornographic media for this purpose, and many clinics allow patients to tote a sperm sample from home as long as it can be brought in promptly.)

The process is certainly more pleasant than much of the prodding and pricking female patients must tolerate. "I think every couple having trouble conceiving should undergo a semen analysis, certainly prior to performing any invasive procedures on the wife," says Dr. Copperman.

VII Misconception: "I'm generally healthy, so I'm sure I'm fertile."

Reality: General health does not correlate strongly to fertility, but a healthy lifestyle is important. Women who smoke throw off their estrogen levels, risk tubal pregnancy, and increase the chance of miscarriage, low birth weight, and birth defects.

Male smokers significantly lower their sperm counts and increase the percentage of abnormally shaped sperm. Moderate alcohol consumption—a glass of wine with dinner—probably won't diminish fertility, but much more than that may cause menstrual disorders and abnormal sperm production.

Doctors also warn against excessive caffeine consumption while trying to conceive: Stick to one or two caffeine drinks a day. "Just say no" to any recreational drugs, as even limited use can affect male sexual function and disrupt ovulation. Being overweight or underweight—20 percent off your ideal weight in either direction—may hinder fertility in women. Moderate exercise is good, but women should avoid exercising to the point where their cycles are disrupted.

VIII Misconception: "I'll get pregnant a month or two after I start trying."