I feel like it's OK to have girl and guy presents, but I also think neutral is fine, and almost goes without saying. I don't know what "typical guy presents" are, actually. I think there is a stereotype for women (fashion, jewelry, accessories, maybe even makeup--though of course not all women). But for men, there aren't as many. A wallet, a backpack; men don't wear tie bars or tie clips or cuff links much anymore.
Maybe the wording would have been better to say, "there will be an equal number of men and women so please make sure your gifts reflect that." Presumably if you know the social group, you can add "and maybe a few that aren't either."