I don't think genetics plays a role in this, to be honest, but I could very well be wrong. Me and my little sister were both full term babies, my little sister was actually 3 weeks overdue. and I've had one preterm baby and one full term baby (currently growing my last baby now). I think it's just our bodies knowing when the time is right.
Ok thank you for these feedbacks
@Kaylynn I agree!
My mom had full or past term babies. I had a preterm. So I’m not sure if genetics have a role in that