^ I would guess that note refers to the researchers postulating that someone who smokes weed is more likely to smoke/do other stuff like cigs, and maybe assuming they're more likely to do other drugs/unhealthy things. Idk if that's even a little bit true, BUT I'll say smoking weed when I was started helped open me up to using other drugs, out of interest and a curiosity to see how they compared. And my weed dealer when I was young even offered me Xanax, salvia, acid, and booze when I was but 15 yrs old hah (not a very responsible dude).
And maybe some people who smoke just go too far and smoke nonstop and eat hella junk food. But that is a generalization for sure; I myself was a swimmer competitively and I did 6-8 hours of cardio a day, 5-6 days a week for years with a very rich and varied diet. All while I was a daily toker as well.
Regardless, I think any blanket statement about " men who smoke weed being more unhealthy" is lacking in its validity. Honestly alcohol does so much worse and I know for a fact people who drink alcohol regularly are more likely to smoke tobacco as well. So to put it shortly: weed doesn't make ur balls shrink or cause impotence or lower sperm count by any quantifiable amount.
I don't recommend any pregnant woman to smoke weed on any sort of basis and hopefully abstain from all drugs of Abuse during pregnancy. But the guy getting a girl pregnant doesn't have to worry about his weed causing his sperm to fail. I don't see any reason why that could remotely be true, or who it could be proven in a scientific way.