There's no wrong answer! And it definitely depends on your partner and their career as well. In my medical school class there were several individuals who had children, a handful who had children during medical school, then many more who had children during residency or after. Do know that during medical school you will be very busy, and intern year of residency is usually very difficult as well. Financially, it's very difficult to have a serious job during medical school, so that may effect your decision. You'll actually have a salary in residency, and a much higher salary as an attending physician. But in the end it's just personal preference and what works for you.