I have a 10 month old and I will be starting at U Mich this fall. My husband works from home. We are planning to have another during med school, and I'll be taking off a year to stay home once #2 is born, since the first year is the MOST important time for baby. It's good to have parents both there as much as possible during the first year, especially with breastfeeding. Most wait until residency to have babies. The situation I have works because I have an awesome husband. Either my husband or myself is able to be there all the time. When we want to take a break and go out on a date, our parents step in. For many, work/family dynamics are pathological because they just do what everyone else does. I say, step back and really think what would be the most logical thing to do. I went against the grain having children young, though my husband and I have known each other since we were 12 and 13.
When I was pregnant, so many people said motherhood would be stressful, childbirth would be unbearably painful, etc. I chose to not believe them - and this ended up being a great choice. Motherhood is awesome for me. I did attachment parenting, so I am still breastfeeding (American Academy of Pediatrics says either breast milk or formula ONLY for the first 12 months, except for the "experience" of food for non-nutritional reasons), and we use baby carriers and slings a lot. My life isn't OVER since I take my daughter everywhere, instead of staying at home all the time isolated, which is the accepted norm. She loves going new places and meeting new people, whereas most babies her age are afraid. She knows how to act because of going out so often, and she is never fussy because she feels secure and loved.
Once you hit year 3 of med school, more time will be spent away. Years 1 and 2 for many schools have lectures online or taped, etc. So, I planned for my babies to NOT be babies at this point, but young children. My husband will be at home with them, along with our friends, who are like family to us.
One thing that may be hard: keeping up a household along with school/career and kids. In my family, we have given up some things, like TV and eating out, and pay a friend to clean. That way, we just worry about our family relationships and work. This is going against the norm again. Most people HAVE to have their 4 hours of cable a day and don't know how to cook a meal without a box. This is our culture. You don't have to buy into it if you don't want to. We have so much more time than many of our friends because we don't watch TV. We make music at home, or read.
Also, you can organize your home so it is a cinch to take care of. That's what my family has done. We don't have clutter; we use a system from a book we read.
Before my current situation, I worked 50 hours/wk, went to school full time, took care of sick family members, and ran student organizations. THAT was stressful. Now, having a happy baby look into your eyes... that's a stress reliever, and a reminder to live in the present and stop worrying about the future.