[SonOfDarkSkies]

He could have also had mumps as a child. At certain ages, the mumps can affect proper development of reproductive organs, the result of which may have been low testosterone. Low T folks often, of course, have low sperm count.

Furthermore, I read a report (the name and identity of which I cannot remember) that indicated that some low testosterone men have adrenalyn surges--are feisty and aggressive--apparent due to absence of the odd calming affect of normal T levels.

[Houghton M.]

The problem could not have been low sperm count. He impregnated women 13 times. The problem was that the babies died, most of them.