They are not under-aged men physically, but they are infants mentally. They know how to build a house but not how to make a home.
If you want to know baby husbands; look for the following:
He keeps malice with his wife
He rejects food because he is angry
He beats his wife
He reports his wife to friends and family members
He keeps a separate room from his wife.
He embarrasses his wife publicly
He calls his wife goat, animal, fool, etc
He loves his mother more than his wife
May refuse to give house-keeping allowance because of a little misunderstanding