Male male 144 Animals 142 Female 98 nonhuman 96 article 94 female 94 animal 86 Organ Size 66 controlled study 62 priority journal 56 animal experiment 54 organ size 52 animal tissue 46 classification 46 growth, development and aging 44 Animal Structures 42 animal structures 42 Rats 40 Argentina 38 anatomy and histology 38 Body Size 36 body size 36 rat 36 Animal Distribution 34 animal cell 34 animal dispersal 34 physiology 34 Mice 30 metabolism 28