WIRED has a critical essay on the movie's gender representation. It's a bit draggy, but it does make a few vivid points and comparisons:
And:
Ava’s predicament really isn’t that different from many female AIs who have come before her, from Metropolis’ Maria to Her’s Samantha to Blade Runner’s Pris. She is an android in female form, and thus she simply reflects how Hollywood has been depicting women—robotic or otherwise—for decades. In Blade Runner, the male replicants Roy Batty and Leon are struggling to change their short lifespans, while “basic pleasure model” Pris helps the cause by draping herself on J.F. Sebastian. In Prometheus, David is intellectually curious, but never sexualized. (Yet when Idris Elba’s Janek accuses Charlize Theron’s Meredith Vickers of being a robot, she responds with “My room. Ten minutes.” Because sex is the easiest way to prove you’re a real woman.)
Think of David in Prometheus; his primary goal was assisting on the mission, not seducing Vickers. As a “male” AI in a film he was given an intellectual pursuit, not a romantic one. Is it possible Ava could’ve convinced Caleb she passed the test with fewer pleading glances and more analysis of world affairs? What would Ava have done to pass if she was a he?