Can a guy get his fertility checked before having kids?

My boyfriend is worried because he found a lump in his right testicle. He went and got it checked and but the doctor didn't feel it. His aunt can't have kids and we don't know why but I'm just wondering if we can get his fertility checked to ease his mind.

If you have a microscope you can check for active sperm at home, good luck.

Well, it would seem rather pointless to have it checked after he has kids.His aunt's inability to have children is almost certainly not related to his own fertility. Male and female plumbing as quite different.And of course he can get tested for fertility. But it is really important that he have any irregularity in the scrotum checked. I wonder why he didn't insist that the doctor check it?