My husband had this issue.
We have decided it is biological, and other fathers we know have agreed and confirmed this. It is very strange because for my husband it went away around the 9 month mark. He can now hear our dd when she cries. We speculate that it is because in the early months the dad is working that he must get sleep in order to provide for the family- some insane instinctual thing. We have no evidence of this only that so many other fathers have been through this and are staring at their wives in the middle of the night wondering what's going on because they have had absolutely NO idea the baby has been crying for hrs and why their wives are so upset!
I know this won't make you feel better. It really sucks. :roll: I don't know how many times I was so angry he was still sleeping while I was up, exhausted!!! What did make me feel better was waking him up regardless, even if the ordeal was over. :wink:
I found that if I needed my dh's help with PU/PD (at the 4 month mark) it was much better to let him take the first round, so the bedtime one. I would go to bed early when my dd did, so if I had to be up at around 1am I had at least 5 hrs of sleep.
He is really great at helping in the night now that he can hear her. :wink: