They promote potentially harmful breast binding for children who identify as trans males . In 2021 they commenced legal action against LGBAlliance claiming that organisation should not have been given Charity status. In 2022 the organisation came under investigation by the Charities Commission regarding the promotion of breast binding for children and associated safe guarding issues . In Oct 2022 one of their trustees resigned following revelation of his participation in a conference hosted by an organisation that promotes services to paedophiles .In July 2023 Mermaids lost their action against LGBAlliance  .
- Why is Mermaids promoting breast binding at events for young people? in The Spectator 5 Nov 2021 https://www.spectator.co.uk/article/why-is-mermaids-promoting-breast-binding-at-events-for-young-people-
- https://www.thetimes.co.uk/article/trustee-of-the-transgender-charity-mermaids-quits-over-speech-to-paedophile-aid-group-jkjn2jrk9. The trustee was Dr Jacob Breslow, a LSE staff member
- Trans charity Mermaids loses challenge against LGB Alliance https://www.bbc.co.uk/news/uk-65340857