Ohio Sen. Sherrod Brown, one of the top Democratic opponents of President Barack Obama’s trade agenda, criticized Obama on Tuesday for what the senator saw as “disrespectful” comments toward Sen. Elizabeth Warren and indicated that Warren’s gender may have played a role.

“I think by just calling her ‘another politician’,” Brown told reporters Tuesday when asked how Obama was being disrespectful to Warren. “I’m not going to get into more details. I think referring to her as first name, when he might not have done that for a male senator, perhaps? I’ve said enough.”

Earlier Tuesday afternoon, Brown told reporters at a news conference that he took issue with Obama’s comments toward Warren in their deepening spat over trade.