Why are there age limits? why is it illegal to marry a 12-year old? Helen of Troy was 12. Juliet and Cleopatra were still teenagers when they became famous. Most heroines of classic novels and poems were underage by today's laws. Thomas Edison married a 16-year-old: was he a sex maniac? The oldest person in the USA, Hester Ford, got married at 14: today her husband would be in jail for statutory rape (2021 update: she died at the age of 116). I am not advocating anything, just stating facts. Medical studies show that the best age for a woman to have children is between 15 and 25 (lowest chances of miscarriage, of birth defects and, last but not least, of the woman dying while giving birth); while the worst age is after the mid 30s. And the younger you are, the more likely you are to cement a real friendship with your children; the older you are, the more likely that the "generational gap" will hurt your children's psychology. Therefore it is more "natural" to have a child at 16 than at 36. In countless countries of the world women have their first child at a very young age, and stop having children at a relatively young age. This is all illegal today in the USA, while it is perfectly legal to get pregnant at 40 or (thanks to medical progress) even at 70. Note that all of these forms of marriage were common in ancient times before the introduction of Christian "morality". Therefore one could (could) find stronger arguments in favor of these forms of marriage than in favor of homosexual marriage (which has been relatively rare throughout the centuries and is penalized if not outright persecuted in just about every society of the world).