Don’t. Just address the invites to the people you want to attend. Baby showers are typically women only. I don’t think you need to be specifically exclusive on this one. It’s usually implied.
DD1: June '16 DD2: March ‘19 :::: Married since 2011 :::: USN Wife ::::
I'd say it depends on what's the norm in your circle. We'll be inviting my male friends and everyone's kids to the shower and while some of my friends did no kids, everyone invited at least some men. So, if your circle is like mine you might want to say something kind and funny to make it clear. Maybe: all guests must be old enough to legally have a drink to help numb the fact that they have never known what it's like to have a president of their gender running the county. I think if you make it clear it's a grown woman only space that people will understand and respect your wishes.
Re: Funny ways to disinvite children and men to baby shower