I noticed while setting up my forum that there are only two options (male and female) for members to select as their gender. I know that people can choose not to select either option, but I was wondering if there's any way to add other options for those people who do not fall into the gender binary?

Well to add other options for gender in totality, we can do this workaround which i believe could work. Please read it carefully.

Users & groups>Profiles
Click on Modify corresponding to the Gender profile field, which is a predefined list.
Necessary Filled: No
Display: Uncheck for both
Display this field for users that are at least : Admins
Save.
What this step does is removes the predefined list of just Male & Female.

Now we will make another profile field where we can add multiple images & the user can choose any one of them.
Users & groups>Profiles
Hit on
Type : Image list
Fill in the details then
Necessary Field:Yes
Display: Check for both
Who can modify this profile field value: member Himself
Then again hit the
Image Address: Add the url of the image
Alternate text: Male
Then again hit the
Repeat this procedure for various options.
After you hit save. There is a option to replace the content, so when you hit this all profiles will have the image that you added first. So all members will have to go in & change it if so required through their profile.

Ah! Thank you so much! I was able to answer a few more of my own questions because of your help!