The Republican made the remark Friday on WHP-TV in Harrisburg when asked about a statement his lawyers made in an August court filing.
The attorneys had said gay marriage licenses have no "value or legitimacy" in Pennsylvania and can't be defended in court. They compared gay couples to children, who can't marry because a 1996 law says marriage is between a man and a woman.
Corbett has called that statement inappropriate. On Friday, he said he thinks "a much better analogy would have been brother and sister, don't you?"
Pennsylvania bans gay marriage, though one county has been issuing same-sex marriage licenses.
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