Zoology 010501 environmental sciences Biology biology.organism_classification 01 natural sciences Sperm Guppy 03 medical and health sciences 0302 clinical medicine Poecilia Trenbolone Endocrine disruptor Sexual selection medicine Animal Science and Zoology Mating 17-beta-Trenbolone 030217 neurology & neurosurgery Ecology, Evolution, Behavior and Systematics 0105 earth and related environmental sciences medicine.drug