1. Pick some numbers between 1 and 20, however many you want.
2. The odd numbers are boys and the even numbers are girls.
3. Numbers 1-5 have to be named after plants, numbers 6-10 have to be named after months or days, numbers 11-15 have to be named after places, and numbers 16-20 have to be named after saints or other famous people.
4. Give them middle names. These can be whatever you want.