It may appear Hillary and Chelsea Clinton always see eye-to-eye, but in a recent interview one topic cracked the facade of the like-minded mother-daughter power duo.

The one issue Hillary and Chelsea don't appear to agree on entirely is transgender self-identification.

In an interview with The Sunday Times, journalist Decca Aitkenhead asked the Clintons if someone with a beard and a penis can ever be a woman, to which Chelsea replied emphatically, 'Yes.'

However, as Aitkenhead describes it, Hillary looked 'uneasy', and blamed generational gaps for being less accepting.

'Errr. I'm just learning about this,' Hillary responded. 'It's a very big generational discussion, because this is not something I grew up with or ever saw. It's going to take a lot more time and effort to understand what it means to be defining yourself differently.'

In an interview with the Sunday Times, journalist Decca Aitkenhead asked the Clintons about transgender self-identification

Decca Aitkenhead (pictured) said Hillary became 'uneasy' when the question was asked while Chelsea shot a 'furious stare' at the journalist as her mother answered

The Clintons sat sown with Aitkenhead to promote the book they co-authored, The Book of Gutsy Women: Favorite Stories of Courage and Resilience.

The book features Danica Roem, the first trans woman elected to a U.S. state legislature.

According Aitkenhead's account, she tells Hillary during the interview that many British feminists of Hillary's generation have a problem with the idea that a 'lesbian who doesn't want to sleep with someone who has a penis is transphobic.'

Hillary nods in agreement, while Chelsea 'stiffens and stares at me', according to Aitkenhead.

The journalist then adds that many women of Hillary's generation are uncomfortable with biological males sharing women's bathrooms.

'I would say that, absolutely,' Hillary nods firmly. 'Absolutely. Yes.'

That's when Chelsea begins shooting a 'furious stare' at Aitkenhead, who points it out to her.

'I'm a terrible actor', Chelsea laughs.

Chelsea then says she is thrilled with the National Health Service's decision to assign patients to single-sex wards according to the gender they identify as, instead of their biological make up.

Chelsea Clinton replied 'yes' emphatically when asked if someone with a beard and penis can ever be a woman while Hillary said 'It's going to take a lot more time and effort to understand what it means to be defining yourself differently'

'How can you treat someone if you don't recognize who they feel and know in their core they are?' Chelsea says.

'And I strongly support children being able to play on the sports teams that match their own gender identity,' she adds. 'I think we need to be doing everything we can to support kids in being whoever they know themselves to be and discovering who they are.'

At this point Hillary looks conflicted.

'I think you've got to be sensitive to how difficult this is,' Hillary says. 'There are women who'd say [to a trans woman], ''You know what, you've never had the kind of life experiences that I've had. So I respect who you are, but don't tell me you're the same as me.'' I hear that conversation all the time.'

Despite the clear tension in the room, the pair say they don't argue about this topic.

But according to Aitkenhead, 'I get the impression they don't like to present anything less than a united front to the world.'