As soon as you become a mother the guilt kicks in.
If you weren't feeling guilty about the possible genetic connection regarding height, I bet you would be feeling guilty about some other aspect of parenting.
Guilt is such a destructive emotion and so hard to shake off but do try.
I am short woman with a short husband and I have a short daughter who has had a short child by a short man....
We all still live and breathe and enjoy life.
Luckily for me being short has never proven to be a problem in fact it has often been an advantage. I hope that will be the case for your son.
Stay in the moment.