title: On call. I've heard that men are making fewer sperm cells than they used to, and birth rates may suffer. What's the latest information?
authors.forename: Harvey B
authors.initials: HB
authors.lastname: Simon
mesh_terms: D005060:Europe; D006801:Humans; D008297:Male; D013076:Sperm Count / Q000639:trends; D013091:Spermatogenesis; D014481:United States