While many royal commentators are convinced that Prince William and Princess Kate will eventually have a fourth child, ITV News royal editor Chris Shipp is not so sure.

Shipp seems to find the speculation amusing, but insists that the crown prince and princess may decide against having a fourth child for environmental rather than personal reasons.

"I went to the maternity hospital with Kate recently, and even before we got to the hospital, I was wondering when we would see the 'Kate's looking at the baby, Kate's getting cranky, Kate's having a fourth baby,'" Shipp told Sky News Australia (via Express).

To be fair, the princess herself has used the word "broody" more than once during their official engagement, and has joked that her husband is worried she wants another.

"We have to remember that William and Kate are already in their 40s, but there's a good chance she'll have a fourth," Shipp continued.

For the record, the Welsh are the parents of George (age 9), Charlotte (age 7), and Louis (age 4).

Shipp further explained that having four children can be environmentally harmful (due to CO2 emissions), which is a very relevant concern for Prince William, who has made it his personal mission to reverse the climate crisis in recent years.

"There is a bit of a serious point to this, Harry has mentioned it before, and now William is campaigning more and more on environmental issues," Shipp said.

"A lot of people are actually saying, for the sake of the planet, we shouldn't have four children. If William had a fourth child, he might be open to that kind of criticism from the environmental lobby."

"But hey, that's their choice. They're a couple, they can choose when they want to have a fourth child or not."

William established the Earthshot Award to support projects that help heal the planet. The award's second awards ceremony will be held in Boston this December.