Yes but he had better have something done about the hernia.
Yes, most likely having a testicular hernia will not damage the ability of the testes to make and transport spermatazoa.
No,but they will get pregnant if the child is having sex with a man
It would depend on where the hernia is located, depending on the location, it may affect a man's ability to perform.
Can be a hernia, have it checked out.
yes. chances of getting a normal child is 50/50
A man living with another woman having a child or children, is very irresponsible because no matter how you word it the child or children are illigitimate.
No
That is the pain of having to make child support payments.
If he is the biological father, yes. That is what counts. If the mother and this man knew he was not the father they have both committed fraud by having him signing the birth certificate. The child have a right to know who his parents are as well.
This depends on the size/placement of a hernia and how it is removed. From what I have been told, it should not do but no one is going to promise you that they will not. I suggest visiting a doctor to have a hernia examined for a more in depth consultation/answer. all the best and dont worry!
3 grams
50-50. In the circumstances you list, each child of theirs has an equal chance of having- or not having- HD.