My wife and I are expecting our first baby very soon. However, I am a heavy sleeper and I am worried that I will not wake up to cries from the baby. Do people generally become lighter sleepers with the knowledge that they have a little one to care for during the night? I am really hoping that I will be able to beat my wife to the crib sometimes so that she doesn't feel guilty when she prods me awake.
It's not possible to say whether you will be a lighter sleeper after your child is born; that's entirely up to your brain chemistry and lots of other variables.
I also don't think that there is one 'generally' here. I became a harder sleeper, my wife became a lighter sleeper, for example. Anecdotally, most of the new mothers I've known became lighter sleepers, and among fathers it's more mixed; perhaps due to the differences in biology, perhaps just small sample size, I'm not sure. Looking around, I don't see any studies (though I don't have access to PubMed, maybe @Anongoodnurse or someone else can find some there), but I see lots of anecdotal evidence like this page supporting my experience - moms become lighter sleepers, dads not as often.
That doesn't mean you can't be helpful, though, even if you do have a harder time waking up when the baby wakes up. You can do more of the bedtime routine, for example, allowing your wife some time to relax (or to go to bed earlier). You can wake up earlier so you're the one waking up with the baby in the morning (that's me, for example). There're plenty of ways to deal with your overall problem if you don't turn into a lighter sleeper.
I also don't know what studies on the subject, if any, have found. But surely there is variation between people, so you'll see for yourself what ends up happening to you.
I am a very heavy sleeper, and my wife isn't. After our first birth, and again after our second, my sleep gradually became lighter as a result of getting used to waking up (with the help of my wife, who was still a lighter sleeper than I).
One way to help this process is to have the baby sleep with you in your bed or in an extension of your bed - on your side. Be sure, though, that your sleep is not so heavy that you might roll over the baby without waking up!
Another possibility is to have you sleep for set periods of time (say, every other day) in the same room with the baby, while your wife sleeps in a different room, and make it clear that it is only your responsibility to take care of the baby and feed her - your wife sleeps straight tonight, and she's not going to come to your aid. With responsibility comes lighter sleep.
Lastly, when the baby reaches the stage of crying her throat out because of gas, both you and your wife are going to be awake together anyway.
Have a great birthing and parenting experience!
I have a reputation among those who have lived in a house with me over the years for being able to sleep anywhere, anytime and through anything. That hasn't changed, but my son crying wakes me up.
You might be the same, you might be different, it really is an experience that nothing and no one can fully prepare you for, but one thing I can say is this. The fact that you're thinking about this sort of thing tells me you're going to do just fine as a husband and father.
Good luck, and enjoy your little bundle.
My boyfriend was a very heavy sleeper and I moved a lot in my sleep. When our daughter was born I admit we slept with her (reason being I was breast feeding, not a good excuse I am aware of now) and for me as soon as either one of them moved I was awake and he become a lighter sleeper as well. Even now (she is 3 now) when she's in her own bed/own room I can hear her instantly.
Interesting example is when you three are in the store and your on the other end, your going to hear her cry and you will know its yours and no one else's. Its cute really.
We have three kids. When I wake up in the morning, I ask my wife if I missed anything between the time I fell asleep and the time my four alarm clocks go off to wake me up. Sometimes, I wake up to find a child who made his way into our bed sometime during the night. No, my sleep did not get any lighter with kids.
However, I have an easier time staying up late (and a harder time falling asleep), so whenever our kids woke up / wake up "earlier" in the night (say, before 1:30 a.m.), I take care of it and my wife can go to bed / stay in bed. (The flip-side of what Joe said.) If you are giving bottles, you can be even more useful at these times.
Bottom line, if you don't become a lighter sleeper, you'll find some other way to pick up some slack.
I was an incredibly heavy sleeper, the heaviest of anyone I've ever known. Since I became a dad, I wake to every little grunt, every little squeak my daughter makes over the baby monitor. I wake multiple times a night searching through the covers trying to find my baby in the bed--even though we've never once let her sleep in our bed (he sleeps in another room). I've been driving my wife crazy. She's not sleeping well because I wake up so often. You never know how you'll adapt.