Sex and violence: the roots of Mexico's teen pregnancy problem Claudia Colimoro still remembers the day she met Rosa, a 12-year-old girl who landed on her doorstep after being sold into sex slavery twice by her own mother and getting pregnant for the second time. Rosa -- not her real name -- is one of hundreds of thousands of teens and pre-teens who get pregnant each year in Mexico, a problem caused by minors having unprotected sex at an early age, but also by horrific violence against women and girls.