Typically, a child can have only two legal parents. If your granddaughter is adopted by her stepfather, your son's rights as a parent would be legally terminated. If your son wants visitation rights -- or any other rights -- where his daughter is concerned, he shouldn't consent to her adoption by someone else.

Grandparents' rights are a trickier subject, but as long as your son has visitation rights he can also facilitate your visits with your granddaughter. If you have a problem later, talk to a lawyer who knows about laws in your state that might affect your rights to see your granddaughter. Learn more about grandparent visitation.