Yeah, I'm not so sure about this theory. Active kids might wear themselves out a bit more, but they are so active its hard for them to relax. More placid children might find it easier. My DS is very active, and will fight sleep very hard as long as there is an opportunity to play some more- and then he will hit a wall and crash!

Nai, I'm not sure its like that for us- I wish it was! DH and I are great sleepers... DS is not so fabulous. Hm, maybe the good sleep gene doesn't kick in until later!!