Nota bene: evolutionary biology. The male's dilemma.
Gallagher
R B
RB
D000818:Animals; D000917:Antibody Formation; D005075:Biological Evolution; D002645:Chickens / Q000033:anatomy & histology* / Q000235:genetics / Q000276:immunology*; D003129:Comb and Wattles / Q000033:anatomy & histology*; D008297:Male; D012727:Sex Characteristics; D013739:Testosterone / Q000502:physiology
D013739:Testosterone