Along with pleasure and bonding, women's sexual behavior with others which can include heterosexual or lesbian sexual activity can result in sexually transmitted infections STIs , the risk of which can be reduced by recommended safe sex practices. This had me on my knees and my head in her lap. Reproductive and developmental toxicology. Report of a case and a brief review of the literature". New Dimensions in Women's Health. The length of the vagina varies among women of child-bearing age.