Dear kyyylie,

A guy can only tell if it's a girl's first time if she has a hymen — the thin skin that may stretch across part of the opening of the vagina, which can make penetration difficult. However, many girls do not have enough hymenal tissue to make it difficult. That's why it is not possible to tell whether or not a girl is a virgin by examining her hymen.

A girl may bleed if her hymen has not yet been stretched open. Some girls stretch their hymens before intercourse during sports or other activities, such as horseback and bicycle riding or through insertive masturbation. So not having a hymen doesn't mean that a girl has had vaginal intercourse.

Hope this information helps!

Take care,

teenwire.com^® Editors

This column is for informational purposes only and is not intended to constitute medical advice, diagnosis, or treatment. If you have a medical problem, please call toll-free 1-800-230-PLAN for an appointment with the Planned Parenthood health center nearest you.