Regarding pregnancy, while I generally believe that there is never a good time to have kids, I think there can be really bad times to have kids. I would guess that residency falls into the latter category.
From a work perspective, no matter how supportive the staff and other residents may be, someone will be covering you when you are out (on maternity leave) and it will be a burden on them (and their families). From a parenting perspective, it is impossible to be both a great resident (or any kind of more-than-full-time employee) and a great parent - there simply aren't enough hours in the day. You can do what most women with demanding jobs do - do your best at both and still feel like it isn't enough on either end.
Maybe I mis-read, but I think your post asked about having children before residency and not about pregnancy in residency. I think that if you had kids before, you just make the best of it - it is what it is. But if you are choosing to start an ortho residency, I think that the wise decision regarding pregnancy, is to wait until residency is over if at all possible. Just my thoughts.