surprising fiancé with gender for his bday

At first we didn't want to know gender til birth but we kept going back and forth on it and decided we would go ahead and find out. My plan is to take my mom to an ultrasound, have the tech tell her the gender then when we go out to eat for his bday and he's opening presents something will be of specific gender. My only problem is we don't know what to get him. And suggestions? We don't want him to know that he will find out gender on his birthday so it has to be something small. I'm not going to know either until he opens whatever it is but my mom wanted some ideas of what to get