I'm in the same situation. I'm interested in grad school, but I have a 1 year old and one on the way. I think grad school would only work for me if I could find a part-time Biology program, because we are committed to being with our children as much as possible.
I'm probably crazy: do other parents sometimes wish that the presence of children wasn't completely excluded from academia in our culture? I once attended a week long seminar in a rural Alaskan town (where I lived at the time), and there was a native lady in the back of the classroom holding and bottle feeding a little one. It was casually excepted as completely normal and good, with some of the other ladies taking turns rocking the child. I had no children yet, but my heart ached to incorporate my future family into my dreams of a career.
If it was treated as entirely normal and excepted, do you think you could get your work done with your children around? I'm pretty sure I could.