Serena Williams' husband Alexis Ohanian wants to end the stigma around paternity leave.
The couple - who married in 2017 - welcomed their daughter Alexis Olympia 23 months ago, and the Reddit co-founder has now said he wants to highlight how important it is for men to take time off to be with their newborn children, despite the "stigma" around it.
In an essay for The New York Times, Alexis said: "[I understand that] not every father has the flexibility to leave without the fear that doing so could negatively impact his career.
"Serena and I were lucky enough to have help at home and many other advantages working in our favour. But even with all of that privilege, including my ability to focus solely on my family and not worry about keeping my job, it was still incredibly difficult.
"Nothing could have dragged me away from my wife and daughter in those hours, days and weeks -- and I'm grateful that I was never forced to choose between my family and my job."
The 36-year-old businessman says he doesn't "blame" men for not taking time off work, but insists the stigma surrounding the stereotype that men are "conditioned to be breadwinners" means it's difficult for many men to agree to paid paternity leave.
He added: I don't blame my dad, or anybody else's dad, for not taking time off after a child's birth. Our culture makes it difficult. The United States is the only industrialised country that doesn't mandate some form of paid family leave.
"Men are conditioned to be breadwinners, [and a man's] sense of duty is often fear-based. Nearly a third of dads think that taking leave could negatively impact their career. We could miss out on a promotion. We could become obsolete. We could get fired. Career fear is powerful."
But Alexis believes taking paternity leave is important, because it gave him the "confidence" that he could "figure this whole parenting thing out".
He said: "Spending a big chunk of time with Olympia when she was a newborn gave me confidence that I could figure this whole parenting thing out. As an only child with no cousins, I didn't grow up around babies; in fact, I had never held one until my daughter was born.
"Two years later, there is no stigma in our house about me changing diapers, feeding Olympia, doing her hair or anything else I might need to do in a pinch. They're all just dad things (not "babysitter" things -- I hate it when people refer to dads spending time with their kids as babysitting)."
Alexis is campaigning for a federal bill for paid family leave, which would allow "birth parents, adoptive parents and caregivers alike" to receive paid leave to care for their brood.