Here's why sexologists say size doesn't matter. Any size penis can provide great pleasure for the man it's attached to. An estimated 95 percent of penises are average size (3 to 5 inches flaccid, 5 to 7 inches erect). Very few are significantly larger or smaller. When women have been surveyed about what they want in a lover, they consistently mention attractiveness, kindness, caring, listening, sense of humor, and shared interests and values. Very few mention penis size. Finally, sex therapists report that women clients almost never complain about their partner's size. As a result, most sexologists say size doesn't matter.