The major thing to consider when joining the navy and having children is that you will be away from home alot. Before joining pass it by your children for approval.
Children need a care giver when you are not available to do so. A power of attorney giving up some of your rights as a parent needs to be in the hands on someone to care for them when duty calls for an extended period.
you will be away from your children for extended periods of time. The Navy takes no responsibility for their care. The Navy will not treat you any different than soldiers without kids. You can not refuse duty assignments because of your family situation