Natural Rights

Hart talks about giving up a persons rights and how the only way that X is responsible and has "control" over Y's actions is if Y surrenders his rights. Does that mean that a mother has "control" over making decisions for her infant if the infant has surrendered his rights to his mother? How would a mother know if an infant has surrendered his rights if the infant can't translate that? This was something I thought about while reading this writing. I believe that an infant can't have rights because he doesn't understand what a right is, therefore the mother should be responsible to make choices for or watch over the infant. But how could the infant surrender his rights, because that is the only way that the mother has "control" over her infant. What would happen if an adult who doesn't have the mental capacity to understand rights an has someone else watching over them? Does that mean that the person watching them has the "right" to make choices in the mentally handicapped adults life? I think Hart would say that the mentally handicapped adult wouldn't have these rights because they have to be able to make the choice or decision to surrender these rights. This would also apply to infants because they don't have the mentally ability to surrender or understand the rights that they may or may not have. This was one thing I thought a lot about because we have been discussing whether infants/babies and animals have rights.