President Obama declared himself a feminist in a Thursday essay for Glamour magazine, and called on men to join him in the fight for gender equality.

"It is absolutely men's responsibility to fight sexism too," Obama wrote. "And as spouses and partners and boyfriends, we need to work hard and be deliberate about creating truly equal relationships."

According to Obama, it is important to model what it means to be a feminist for his daughters, Sasha and Malia, so they'll know what to expect from other men.

"And yes, it's important that their dad is a feminist, because now that's what they expect of all men," he wrote.

Obama said attitudes about harassment of women must be altered in every setting, so even women "daring to go online" don't encounter harassment. And, he said men should not be intimidated by successful women.

"We need to keep changing the attitude that values being confident, competitive, and ambitious in the workplace — unless you're a woman," he said. "Then you're being too bossy, and suddenly the very qualities you thought were necessary for success end up holding you back."

Likewise, he addressed the current election and the significance of Hillary Clinton's nomination as a presidential candidate.

"This fall we enter a historic election. Two hundred and forty years after our nation's founding, and almost a century after women finally won the right to vote, for the first time ever, a woman is a major political party's presidential nominee," he wrote. "No matter your political views, this is a historic moment for America. And it's just one more example of how far women have come on the long journey toward equality."

In June, the White House sponsored a White House Summit on the United State of Women, which featured speakers including Michelle Obama to address gender equality issues.