Sperm is smaller than the holes between the fibers in your underwear, so your semen can pass through and come in contact with her vagina, and she could get pregnant. The risk is small, but it's not zero, so don't risk it.

Herpes is a virus that causes blister-like sores in the mouth and genitals. It's most contagious during an outbreak, but it can be passed by an infected person at any time. Since it's not airborne, you won't get it from touching you mom's clothes or sitting on the toilet after she has. It's unlikely that you'll catch genital herpes from anyone without direct contact with their genital area, says William Ledger, MD., a gynecologist at Cornell University Medical Center/ New York Presbyterian Hospital. The only way you could catch it from your mom is if you wore her underwear immediately after she did without washing it. Not likely, right?

You most likely have nothing to worry about, Erin. Some girls are born with Mayer-Rokitansky syndrome ("Absent vaginas"), a condition in which the vaginal canal is smaller than normal and has to be stretched to an average size. But it's extremely rare (only 1 in 5,000 girls in the U.S. has the condition), says Cathryn Tobin, M.D., author of The Parent's Problem Solver. The doctor stretches the vagina by inserting a thin plastic tube called a dilator into the vaginal canal. Most girls do experience soreness the first time they have sex because their vaginal walls expand from the pressure of the penis. But the pain is natural. If you're scared to have sex, it might be because you haven't found the right guy yet. So consider those things before you have sex for the first time.

Absolutely not, Heather. Lots of women don't experience orgasm until they're in their twenties—after they've had more experience with guys and feel more comfortable with their bodies. Orgasm usually occurs when arousal builds up and causes the muscles in your genital region to tighten and release in a wave of pleasure, says Howard Glazer, Ph.D., clinical associate professor of obstetrics and gynecology at Cornell University Medical Center. Research shows that 24 percent of women have trouble reaching orgasm either alone or with a partner, so you're not the only one! And keep in mind that you're young, so you have plenty of time to experience it.