Like I said before with the names,deciding the gender of a OC may seem easy but it's more difficult than you think. Deciding the gender of your OC is easier than the name,so this may be kind of short. Deciding the gender is like the question yes or no,girl or boy. These are the 2 main genders but, if you want more options, there are other,and transgender.
Other things you can do with your character's gender is to make your character a girl and make a note that people think that she is a boy or vice versa a boy who people think is a girl. This will affect most of your OC's design. If you want to do this, then think about what makes people believe that your OC's is the opposite gender.
Some of these things include-
-your OC's hair(your boy OC may have long hair and your girl OC may have very short hair)
-your OC's clothing(your boy OC may were female clothing,if this is the case come up with a reason why and your girl OC may wear boy clothing,like I said before come up with a reason why.)
-your OC's a cross-dresser(this is technically the same as clothing but this has a reason as to why your OC wears the clothing of the opposite gender. Cross-dressers WANT to wear clothing of the opposite gender)
-your OC's name(this rarely makes people believe that your OC has a different gender but,it's good to name your OC a name that is for both genders if you OC is mistaken for a girl/boy. For example the names Alex,Eli,Frankie,Sam,and Charlie can be used for both genders)
That's all I have for your OC's gender.
Well here's the update, Thank you for reading!:):):)