Yup, I think your DH has it spot on! My grandma had 5, and her mum had 5, and for all of them it was boy=m/s, girl=no m/s - in fact, my grandad got boils when grandma was pg with mum and my aunt. My mum had m/s with my brother and really bad m/s with me (for nine months), then nothing with my sister. Her sister had m/s with her son. But 2 is a bit of a small sample size. And it depends on the individual woman, not just what happened to someone else.

Shame my great-great-grandma isn't around, she had 13 and she'd be able to tell you a bit more!