Britain is overpopulated and so using artificial female hormones for birth control. (Women are on the pill.) These hormones enter the food chain, eg via fish, and get more concentrated as one goes higher up the food chain, eg in fish eating animals like polar bears.
Polar bears might be a bit warmer and have further to swim for food, but I think the effect on the population from global warming might be secondary to the effect on the population from male polar bears having a c**t instead of testicles.
Genital disruption in other wildlife species
In many mammalian species (including otters (NBS,1996), mink (Harding et al, 1999), whales (Michaelian et al, 2003), polar bears (Wiig et al, 1998), black and brown bears (Dunbar et al, 1996; Cattet, 1988), panthers (Facemire et al, 1995), and deer (Veeramachaneni et al, 2005)), there are also now reports of genital disruption, including un-descended testes and/or shorter phallus and/or intersex features. Indeed, the endocrine system has been conserved in evolution, so all species will likely be vulnerable.