shared by Richard Hemmer on 06 Feb 08 - Cached
The Bible itself says that the human lifespan is between seventy and eighty years (Psalms 90:10), and given the advances in lifespan brought about by improved nutrition and modern medicine, we can safely use the higher estimate. We should then ask why, if sex is intended for procreation, it is all but impossible to use it for that purpose for about half of our natural lives. Even during the biologically brief window of maximum fertility, our rate of conception is significantly lower than that of most other animals. If sex's only or primary purpose is procreation, then it would seem to be a badly designed mechanism indeed, considering how inefficient it is for that purpose.