Obstetricians specialize in treating woman's reproductive health from the time she gets her first period until post-menopause. Any condition affecting the reproductive system, such as the cervix, uterus, ovaries, fallopian tubes, or vagina, is diagnosed and treated by an obstetrician. A gynecologist also performs recommended examinations such as breast exams, pap smears, and pelvic exams. Gynecologists also provide advice on sexual issues, such as sexual practices with responsibility, contraception, and protection against sexually transmitted diseases.