After searching for a gender userfield, I was unable to find one so I sat down and here it is. It is complete with images. The user can select their gender in Edit Profile and when their profile is viewed it will display a small icon representing the selected gender. Supports male, female and transgender. Comes with two sets of icons to choose from and the necessary files to use both sets. The second icon set and files are in the extras folder. Complete installation instructions in the readme file.