title: How representative are semen samples?
mesh_terms: D000328:Adult; D004542:Ejaculation; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis; D008297:Male; D008418:Masturbation / Q000523:psychology; D012661:Semen / Q000032:analysis; D013048:Specimen Handling / Q000592:standards; D013094:Spermatozoa / Q000032:analysis