Some reason why you are so shy about whether there is a right of old men to ‘marry’ 20 or 30 pubescent girls?
I see what your interest are.
If some one is a child they can be forced and easilly manipulated. They should be protected by their parents, society, and the government by lecherous men who ask starnge questions on the internet. Also, I agree that they cannot enter into contracts.
Your question is out of left field and deserves and more negative response, but I chose to answer it respectfully.