The should also warn girls that sperm/semen affects their immune systems rather dramatically. God designed girls so that our bodies wouldn't reject a foreign body, like a baby by making it possible for our immune systems to be compromised. It's fascinating how God created our bodies to work, we were designed to be with one partner. Having multiple really does a number on women's immunity. It's part of the reason that the swine flu is so devastating to pregnant women, their immune systems are compromised by pregnancy and the flu is deadly to them. Having multiple partners, compromises a woman's immunity to viruses and disease greatly.