Is it leagal for a landlord to rent a room to a family that has a child knowing that a registered sex offender lives in the residence?

is it leagal for a landlord to rent a room to a family that has a child knowing that a registered sex offender lives in the residence??
Yes. The landlord is not responsible for enforcing Molesters re-entry requirements.

However the sex offender is required to report his address to the Authorities. And if not allowed to live near a child may be required to move. The Government can't require the child to move, but were I the child's parent, I would.