Harvard University is starting to ask its students which gender pronouns they want to be referred by.

The registration form includes typical options like "he" and "she" but also gender-neutral options like "ze." It gives new options to transgender students, and those who don't identify as male or female. In the past, forms required them to choose between "male" and "female."

Other schools that recently embraced those pronouns include American University and Ohio University.

Experts say colleges are changing as they recognize the growing population of transgender students. Many have also created campus housing geared toward transgender students.

But changes have sparked backlash at some schools. The University of Tennessee posted a guide to gender-neutral pronouns on its website, but removed the post after it drew outrage from state senators.