Germ-free mice with perfect hormone regulation had larger testes and healthier livers with higher testosterone levels compared to conventionally raised mice.

“when you looked at the histological features of these germ-free mice that were bred in an environment where there was perfect regulation of hormone production between the testes and the brain and then in addition to that excretion there was no interference whatsoever you looked at their your their their histological um examinations for their testes they were larger better develop their liver had higher testosterone levels extra intestinally they were a healthier looking mouse than the conventionally raised mice”