The email comes on a delicate day on gay rights for the Obama administration. On Sunday Biden said that he is "absolutely comfortable with the fact that men marrying men, women marrying women" in an interview on NBC's "Meet the Press." And, asked about it on Monday, Secretary of Education Arne DuncanArne Starkey DuncanParkland survivors talk gun violence with Chicago high schoolers Trump administration is putting profits over students Chicago to make future plans a graduation requirement: report MORE also came out in support gay marriage. The White House then spent the day struggling to reconcile those comments with Obama's position that he is for civil unions but not gay marriage, although he has said he's "evolving" on the issue.

"I have no update on the president's personal views,” White House Press Secretary Jay Carney told reporters Monday at a briefing dominated by questions about Biden's comments. "What the vice president said yesterday was to make the same point that the president has made previously, that committed and loving same-sex couples deserve the same rights and protections enjoyed by all Americans and that we oppose any effort to roll back those rights."

Obama is in a tough position — some of his top donors are gay and he's had strong support from the gay community, but gay marriage is less than popular in polls with many key voting groups including African Americans, Hispanics and white Catholic voters. 

The email did not mention Biden's comments.

This post was updated at 6:05 p.m.