Tony Perkins, president of the Christian conservative Family Research Council (FRC), has criticized former Supreme Court Justice Anthony Kennedy's assertion that bans on same-sex marriage hurt children.

Kennedy wrote the court's majority decision in Obergefell, the 2015 case which found that gay and lesbian couples have a constitutional right to marry.

Speaking with Bloomberg TV, Kennedy said that he viewed the case in terms of how it affected the children of gay couples.

“As I thought about this, and I thought about it more and more, it seemed wrong – unconstitutional – to say that over 100,000 adopted children could not have their parents married,” Kennedy said.

In a press release, Perkins, who has close ties with President Donald Trump and the Republican Party, said that Kennedy “has it all backwards.”

“As social science will tell you, Justice Kennedy has it all backwards,” Perkins wrote. “Although he said he tried to take everything into consideration, he obviously neglected the one thing that judges in his position are called to consult: the Constitution.”

As evidence, Perkins pointed to an American Thinker column by Nancy Pearcey, in which she stated that allowing gay couples to marry harms “all children.”

(Related: Study: Children raised by gay couples healthier, happier than general population.)

FRC has been labeled a “hate group” by the Southern Poverty Law Center (SPLC) over its anti-LGBT rhetoric.