“How do I ask people their gender?”

My answer to this is “Don’t.” There is no point in conversation, business, or services where you need to know people’s gender.

If it is a gender-based service, just list eligibilities and ask them if they fit them.

If wrapped holiday gifts are gendered, first of all consider stopping this practice.

In any case, really interrogate that feeling that says you need to know someone’s gender. It probably isn’t even your own thought.