Write a nice list of Attributes and make enough copies for each guest. Your list can include these: Eyes, Nose, Smile, Ears, Hair, Forehead, Chin, Legs, Hands, Feet, Personality, Butt, Toes, Intelligence, Humor, Lips, Navigational Skills, Sleep schedule, Cooking skills, Patience meter, Charm etc..
Pass pens/pencils along with this list and have guests write down next to each attribute who they think baby will take after. Mom or Dad. Then Mom2be will do the same. Whoever matches the most to moms will win a prize!