What is clear, according to Halden, is that the impact of plastics on human health varies depending on who is exposed and when. The groups most at risk for toxic exposure are infants and pregnant or nursing mothers. An article from Arizona State university goes into this in more detail: https://biodesign.asu.edu/news/perils-plastics-risks-human-health-and-environment What we do have slightly more definitive research findings on, is the effect of plastic ingestion on fish. Nature published a report from the University of California, Davis, that found chemicals from plastic ingestion transfer from the gut to tissues in fish. Causing liver degeneration and disease and tumour development. Rochman, who worked on the study states, "We found that when the plastic interacts with the juices in the [fish's] stomach, the chemicals come off of plastic and are transferred into the bloodstream or tissue." http://www.nature.com/articles/srep03263 She adds that her marine toxicology research has lead her to reduce her own fish intake and she has cut out certain species altogether. Fish exposed to microplastics have also been found to have a lower hatch rate (The Journal, Science). This would fit with plastics causing hormonal imbalance. http://www.nature.com/articles/srep03263