The Duke and Duchess of Cambridge have been urged not have anymore children.
The royal couple are reportedly thinking about giving their son George, four, and daughter Charlotte, two, a little sibling in the near future, but the news hasn't sat well with the family planning organisation Having Kids as they've written to the pair "respectfully urging" them to "consider forgoing having a third child."
The letter, according to the Daily Star newspaper, added: "As degraded as the world's environment is today, none of us can imagine what the world would be like if fertility rates had not been halved in the 20th Century, below three children per woman. The future of your country will be defined by the impacts of climate change."
The San Francisco-based organisation went on to encourage the couple - who got married in 2011 - to set a good example by modelling "a sustainable small family."
The letter explained: "Of course, we know that Prince George and Princess Charlotte are certain to have wonderful lives, protected from the deprivations of poverty and the threat of environmental degradation.
"They will receive optimal amounts of care and attention, as well as the best possible education. But the same can't be said of every future child."
The open letter, which was signed by executive director Anne Green and president Carter Dillard, was sent to the royal family a few days after she made a throwaway comment about having more babies during a recent engagement in Poland.