My older two (5yrs and 3 yrs) share a room....but both girls. Since DD#1 has started school this year, we have noticed she likes to do her own thing more- read on her bed (or try too....), colour in on her own etc. I defn think they need they're own space....which is why we have a draftsman coming to our home tomorrow to draw up plans for yet another extensoin......

They have toys in their room....a) to get outta my hair b) they have soo many toys there is simply no more room in the play room....

In your situation...i dont know....its a 2bedder your living in right ??? I was going to suggest a wall divide thingy (you can get from ikea), but bunks dont really work that way....for us, i think its going to get worse, before it gets better.....thus the reason i think they all need their own room. I know i didnt have my own room till i was 13 (i am 1 of 4 girls). I dont know about different sexes though....what do you plan to do when he is say 7 and your little girls is 4-5 years....??? Maybe they are just warning you for what is in store......sorry, not much help.....

Good luck though....