The Duke and Duchess of Sussex only want two children.
The 34-year-old prince has admitted becoming a father to their three-month-old son Archie has made him "see the world differently" and he now only wants a "maximum" of two kids in order to help protect the environment.
Speaking during an interview with conservationist Dr Jane Goodall as part of his wife Duchess Meghan's edition of British Vogue, he said: "Surely, being as intelligent as we all are, or as evolved as we all are supposed to be, we should be able to leave something better behind for the next generation."
Ms Goodwall - who is one of the signatories to the Thriving Together campaign - urged that the environmental crisis won't stop until there's greater access to contraception in developing countries.
She previously said: "Women everywhere must be able to choose whether to have children, how many children, and the spacing between them. This is critical for their own wellbeing. But, they also need to be equipped with the knowledge as to how their choice affects the health of the planet and thus the future of their own children. For we are part of the natural world and rely on its services for our very survival."
Harry's 37-year-old wife - who was known as Meghan Markle before she married the flame-haired hunk last year - hopes this issue of Vogue will show people the "power of the collective".
Writing in her editor's letter, she said: "But more than anything, this issue is about the power of the collective. In identifying our personal strengths, it is anchored in the knowledge that we are even stronger together. You will find that spirit of inclusivity on the cover: diverse portraiture of women of varying age, colour, creed, nationality and life experience, and of unquestionable inspiration. Some, I've had the pleasure of meeting and enlisted personally for this issue, others I've admired from afar for their commitment to a cause, their fearlessness in breaking barriers, or what they represent simply by being. These are our forces for change. And among all of these strong women on the cover, a mirror - a space for you, the reader, to see yourself. Because you, too, are part of this collective."
- Bang Showbiz