I have heard that too. I have two children myself but some of my instructors have confided in me that they are not sure about my classmates who have no children and have never worked in childbirh setting.
It is defintely a crazy double standard. Most people wouldn't blink an eye at hiring someone with no uterus but if you have one you better use it
I came into my desire to be a midwife through having my own kids. I do sometimes wonder about my classmates who have never experienced a birth (as a witness or player), supported a woman in labor, or participated in gyne care. I think they can still be great midwives, but I wonder if their perceptions will change once they experience birth in all of its glory and lack thereof. But I have never heard of surgeons getting a couple of transplants under their belts before med school, so same principle- although most will at least have volunteered in a health care setting.
If it were my husband, I would say he is just trying to be funny and doesn't realize that his comments are a little rude. Good luck with everything!