Can families with kids visit bangkok's rooftop bars?

It is absolutely no problem as the rooftop bars are in fact rooftop restaurants. Its in the open air and they have no dark bar atmosphere anyway. The nicest ones in my opinion are the Sirocco bar at the State Tower and the Moonbar at the Banyan tree hotel. You also have a great view from the Baiyoke tower. There is a restaurant there, but its not in the open air.