‘I was very excited to spend my life alone, to never get married, to never have kids,’ she recalls. ‘People would be like, “Do you want to hold the baby?” I was one of those who’s like, “No, you keep it. ”’

They live in the leafy suburbs of Philadelphia, balancing parenthood with full-time jobs as co-chief-executives of a travel company, writing books about pronatalism, and their non-profit projects (to which they donated 44 per cent of their post-tax income last year). They project an image of accentuated preppiness, dressing in ultra-crisp country club, business casual when photographers visit, and are effusive and open to the press. Malcolm starts our interview by saying, ‘Absolutely spectacular to meet you!’

Both dealt with adversity in their own youths. Malcolm, 36, was held by court order in a centre for ‘troubled’ teenagers, where he was told by staff that if he resisted they would simply invent new infractions to keep him locked up. Read More >