Can a man have child with only 1 testicle?

Yes, a man can have a child with only one testicle.

Testicals produce sperm, and only one testicle is needed to produce enough sperm for fertilization. In fact, some men are born with only one testicle and are still able to father children without any fertility issues.

However, it is worth noting that having only one testicle may decrease the number and quality of sperm, which can make it more difficult to conceive.