I agree with mis_tree that its unlikely that he will change his mind when your son is born. He may just be thinking that ignoring you that he can go on with his life. Males are very stupid in that way, of course he can't just move on, he got you pregnant and he should stand up and be a man but unfortunately it never goes that way.

I honestly think that for your sake and your sons that you don't try for child support, if he is going to deny your son then your son is better off not knowing him at all, my brothers father has denied being his father but yet is in his life... he wont sign his birth certificate and my mother is totally against having "unknown father" on his birth certificate but she's had to register and sadly thats whats going to be on it.

But despite that you will be eligiable for the single parent pension.

I am so sorry you are going through this, but at the end of the day don't press too hard as it will just hurt you, and as for telling your son about his father just say it didn't work out and then when he is old enough to understand you can go into detail.

Good luck