Nine News Australia host, Amber Sherlock, prompted O'Keefe to speak on Meghan and Harry's decision to only have one more child after Archie.
"Advocates for population control and climate change have praised the Prince saying one less child particularly in a rich developed economy is the most effective environmental action you can take. Emily, do you think climate change is really on people’s minds when they are deciding how many kids to have?" Sherlock asked.
"Well some people don’t have a choice on how many kids they have and I’m sure that is not on their mind," the Royal expert replied.
While O'Keefe admitted having only two children was a good idea for the socially conscious royals, she wasn't convinced that the environment was their sole purpose for the decision.
"Meghan Markle is 37 and we know women’s fertility really goes down after the age of 35. So he could only say that they are having two kids because that might be the reality for them," she said.
"It could be their way of saying we are doing it for the environment but it could also be the reality for them," she reiterated.
The Nine News host agreed, stating, "He is probably doing the right thing by Meghan by saying we are just going to have two. Because maybe that is all she can have...She has got an older maternal age, we know this leads to fertility issues."
Throughout the interview, Prince Harry also admitted he was "terrified" of the environmental issues facing the planet and the world his son will grow up in.
"What we need to remind everybody is: these are things that are happening now. We are already living in it," the 34-year-old admitted.
The Duke of Sussex acknowledged that while being a father had definitely opened his eyes to a deeper perspective on environmentalism, he had always been passionate about conservatism.
“I view it differently now, without question. “But I’ve always wanted to try and ensure that, even before having a child and hoping to have children."