Seventy percent of Americans make love for 15 minutes to one hour.

Most men's erections are five-and-a-half to six inches long. Although men's penis sizes tend to vary greatly when they're soft, the smaller ones expand more when erect than the larger ones.

Rates for male sterilization have dropped slightly over the years, while rates of female sterilization have gone up.

Forty-two percent of American women usually have orgasm during sex with their primary partner, 29 percent always have orgasms during sex, 25 percent sometimes or rarely have orgasms, and four percent are not orgasmic at all.

At any one time, one in four people are daydreaming about sex.

The average woman has sex three times a week.

Ninety percent of men want to have children.