An Associated Press article notes advice to Hillary Clinton to drop the use of gender in her campaign:

Clinton has stopped explicitly mentioning her role in history and joking about being the “youngest woman president.” That’s by design: Those kinds of direct appeals weren’t working with voters.
“De-emphasize the ‘first’ talk,” advised a research report done by Emily’s List. “They already know she’d be the first woman president,” the report said of donors, “but we don’t get anything by reminding them.” (link)