The former talk show host who has made two unsuccessful runs for the White House made the comments Monday night in an interview with Sirius OutQ, a satellite radio station that provides programming aimed at gays and lesbians.
After saying homosexuality is "selfish hedonism," Keyes was asked if that made Mary Cheney (search) "a selfish hedonist."
"Of course she is," Keyes replied. "That goes by definition."
Liz Cheney (search), Mary's sister, refused to comment Wednesday during a televised interview.
"I guess I'm surprised, frankly, that you would even repeat the quote, and I'm not going to dignify it with a comment," she told the interviewer.
The Log Cabin Republicans (search), a gay and lesbian organization, denounced Keyes' remark.
"In a political career defined by failures, this is a new low for Alan Keyes," executive director Patrick Guerriero said in a statement Wednesday. "Attacking politician's children is beyond the pale, even for an extremist like Alan Keyes."
In the days before the Republican National Convention, Dick Cheney spoke at some length about the fact that Mary is a lesbian and his view of gay relationships. His tacit support for states' rights on the issue of same-sex marriage and less-than-ringing endorsement of President Bush's push for a constitutional amendment to ban gay unions drew criticism from several conservative groups.