The straight teenage protagonist of the romantic comedy “Adam” is dealt a lot of lucky breaks over the course of this often charming and occasionally aggravating coming-of-age story. But Adam’s first jackpot comes in the opening minutes when his cool older sister, Casey (Margaret Qualley), invites him to stay with her for the summer. Casey is a lesbian living in New York, where she flits among her many queer friends in political protests and sex clubs.

Adam (Nicholas Alexander) is open to learning about Casey’s community, but his learning curve gets a lot steeper when he meets Gillian (Bobbi Salvör Menuez), a cute lesbian who takes a liking to him. Based on the company he keeps, Gillian assumes Adam is a trans man; he doesn’t correct her. Instead, he commits to a lie, pretending to be trans to hold on to his dream girl.