Ronald Reagan, perhaps the most revered icon of US conservative politics, would have supported gay marriage.
So says his daughter, Patti Davis.
In an interview with the New York Times, Ms Davis says her parents had long-term friendships with same-sex couples and that they were treated like family.
"I grew up in this era where your parents' friends were all called aunt and uncle," Ms. Davis told the newspaper. "And then I had an aunt and an aunt. We saw them on holidays and other times."
She added: "We never talked about it, but I just understood that they were a couple."
However her half-brother, conservative author Michael Reagan, has taken a strong stance opposed to same-sex unions.
In his own op-ed piece, Mr Reagan called gay marriage a "slippery slope" that would lead to "alternative relationships and the unconstitutionality of any law based on morality. Think about polygamy, bestiality and perhaps even murder".
Ronald Reagan's tenure in the White House in the 1980s is frequently viewed as the beginning of the rise of the modern Republican party.
Ms Davis told the Times that her father's opposition to government intrusion into the lives of private citizens would also push him toward supporting same-sex marriage.
The Gipper, who passed away in 2004, would have turned 102 this year.
The siblings' comments come as the US Supreme Court weighs two cases that challenge laws that prohibit government recognition of gay unions.
The high court's decisions on those cases are expected in coming months.
Public acceptance of gay marriage has been growing over recent years, with some opinion polls now showing close to 50% of Americans favour it.
Several prominent politicians have announced their support of the matter over the past few weeks, including former Secretary of State Hillary Clinton and Republican senators Rob Portman and Mark Kirk.