Putting a link to this research paper by Canadian scientists studying fish runs after a few folks asked about it. This is one study, there are others you can also find that show how all the synthetic and estrogenic substances in our personal care products, birth control pills, anti-depressants, etc are affecting fish development.
Municipal wastewaters are a complex mixture containing estrogens
and estrogen mimics that are known to affect the reproductive
health of wild fishes. Male fishes downstream of some wastewater
outfalls produce vitellogenin (VTG) (a protein normally
synthesized by females during oocyte maturation) and early-stage
eggs in their testes, and this feminization has been attributed to
the presence of estrogenic substances such as natural estrogens
[estrone or 17-estradiol (E2)], the synthetic estrogen used in
birth-control pills [17-ethynylestradiol (EE2)], or weaker estrogen
mimics such as nonylphenol in the water.
Read more here: