ARE you gay? A small but growing number of colleges want to know.

This year, the Massachusetts Institute of Technology and the University of Iowa added questions about sexual orientation to their undergraduate applications, joining Elmhurst College in Illinois and the law schools at Boston University, the University of Pennsylvania and the University of Washington.

The intention, admissions officers say, is to send a message: You are welcome.

Iowa added “transgender” as a third possibility in its required gender section, plus an optional question: “Do you identify with the L.G.B.T.Q. community?” In a pool of 21,500 first-year applicants, 488 answered “yes.” The students — some of whom may be straight, given the wording of the query — received an e-mail from Iowa’s chief diversity officer describing support services for gay students. “It’s not any more intrusive than that,” said Michael Barron, the admissions director.

Officials insist that identifying as lesbian-gay-bisexual-transgender-questioning does not affect chances of being admitted. But it can pay off. At Elmhurst, which began asking about sexual orientation in 2011, an admitted gay student becomes eligible for a diversity grant usually worth one-third the cost of attendance (currently about $11,000). Two to three percent of applicants identify as gay.

To make it easier for students to fully disclose who they are, steps are taken to protect privacy. Iowa doesn’t transfer the statement to a student’s permanent file. M.I.T. anticipates the chill effect of nosy parents proofreading over shoulders, according to Stu Schmill, dean of admissions. Its application now asks: “How would you describe your sexual orientation/gender identity?” On completing the electronic form, applicants get a PDF version to check over before pressing “send.” But gender identity does not appear, just in case students don’t want to share that information with parents.