They may be just five years old, but twins Ava and Alexis McClure have already racked up millions of followers online.

This popularity stems largely from the adorable videos shared weekly by their parents Justin and Aminat, whose own discussions of their interracial relationship and differing cultural backgrounds have made headlines in the past.

Now, the family is being written about for a more surprising reason: according to a series of unearthed tweets, dad Justin has a history of making jokes based on racist stereotypes online.

Naturally, plenty of people have pointed out the irony that Justin profits from his black wife and daughters; others described the family as “toxic”, and generally bashed him for his ignorance.

The family responded to the controversy with a video depicting a sit-down conversation between the two parents.

After clarifying that the couple did not know each other back when the tweets were posted, Aminat asks: "Do you understand that those comments could have come from the mouth of someone spewing racist hate?”

Justin then replies:

I know I'm not a racist, but I look at the things that I said. Would a racist person say those things? They would.

He then argued that, as a white man, it isn't his place to decide whether or not comments are racist, and that his tweets came from a place of "white privilege" – the mentality of “I'm a white guy, I can say what I want and then brush it off.”

Aminat also expressed frustration at being forced to defend her own characters, as well as making a vital point about racism:

You don't get a pass because you have a black wife.

But the video then dragged up more controversy in the form of an inconsistent timeline – Aminat says in the video that she and Justin didn't meet until 2014, which would make it impossible for him to have biologically fathered the five-year-old twins.

She later clarified in a separate video that Justin adopted the twins, and that he is “the only father they have ever known.”

Since then, rumours have swirled that the father of the twins – borne from a relationship she describes as “abusive” – is a man named Jeff Pestka.