We just did this at the end of July. We had a "Texas Style Baby Shower" I did red, white, and blue invitations but put little baby footprints on the inside.
We simply said "Is it a bbq or a baby shower?" "its BOTH"
Join us for an afternoon of great food and lots of fun at a coed baby shower to celebrate..."
It can definitely be done. Just don't make it too frilly and if you mention food, the guys will be all over it!