I am an MS4 - so I can't speak about residency, but from my pathology elective I can tell that keeping my family together will be a lot easier during residency than it has been so far in med school.
My daughter will be turning 4 in November. So I've never been a med student without also being a mom, in fact, I interviewed 8 1/2 months pregnant. Before that, I was much more type "A" (although some of my friends would insist that I still am). Its hard. Really, really hard at times. Parenting is the biggest challenge I have ever known, and I haven't exactly led a coddled life. It takes a long time to find your feet again after all of your basic assumptions about life are turned upside-down (for example: believing that you can plan on when you can sleep and when you can't, that you can go to the bathroom undisturbed, and of course the most important assumption that somehow you will get through all of this without ever once losing your ****, blowing up at your husband or sticking your kid in front of the tv for an unreasonable amount of time.) But I need to calm down already, it has been a crappy day (for reasons thankfully unrelated to my immediate family.)
If you are still reading this post than you are still optimistic enough to think I have something good to say about it all, something encouraging. Well, I do. Plainly put, raising my child has brought out the best in me, it has humbled me and she gives me more joy than I could have every imagined. There is no right time to have kids, and your time will from then on be governed by a kind of day-to-day mentality, but you learn the tricks (routine, routine, morning childrens show while you get ready and white lies where necessary: ie, yes, you have to stop picking at that bleeding hangnail because once there was a little girl who picked at her feet until one morning when she woke up and they had both fallen off altogether.) In other words, you get through it, you give up a little of yourself and find you are richer for it.
Sorry I have rambled. Like I said, CRAPPY day, but I hope I can at least change the karma here a bit and help someone else..
S.