The Gender field within the 360Alumni data schema can be setup using custom fields, and gender is automatically set to be custom field #1. We recognize that each organization may have different preferences in the options you provide for alumni users when selecting their gender on their profile. We do have our standard gender field on the user record import template, which will correspond to the special custom field 1 location.
To set this up, navigate to the admin dashboard < general settings < user profile fields page. On the right hand side click the button 'add custom field', type in Gender as the title, and select 'checkbox options'. Then you can add as many different options as you'd like to appear. (See below example)