what is the purpose of the human body producing different hormones at various stages throughout the life span?

Answer 1

Regulation! Likewise if you are female well the body is designed to give birth but only up to a certain age and then no more. Men well they need to multiply and supply the other half of the genetic code, so are looking for the best of the crop in females, or what they consider to be good breeding genetic code. The purpose it to maintain the Human Race.