Aaah! The firstborn! Wait 'til you get to the second, or maybe even the third or fourth and you will realise that those little darlings will kip through a nuclear blast in a firework factory if they're otherwise healthy. It's actually good for them - means as they get older they won't be woken at 2.00 in the morning by the neighbours coming home from their night out.
When we had my eldest, hubby was in a rock band and DC would doze off in the same room at rehearsals. Likewise the youngest who would similarly snooze through the noise of several dozen racing motorbikes revving away as they for races in the ciruit paddock. No ear defenders then, either, although I'm happy to report that they both seem not to have any hearing issues in their late thirties, fortunately.