Causality and association--more than just different shades of gray.
Morgentaler
A
A
D000328:Adult; D006062:Gonadotropins / Q000097:blood*; D006801:Humans; D007006:Hypogonadism / Q000097:blood* / Q000209:etiology*; D008297:Male; D012420:Running; D013739:Testosterone / Q000097:blood
D006062:Gonadotropins; D013739:Testosterone