There are only two ways that I know of to get your baby into the United Federation of Planets. Either send him/her into the future or buy them this Star Trek United Federation of Planets Onesie to make them an honorary member.
Baby Spock probably had one of these. This onesie is available in 6, 12 and 18 months sizes. It’s a 100% cotton high-quality navy blue infant onesie that is machine washable. That last bit is ultra important because babies poop themselves.
Your baby will be the coolest for just $17.99 from Entertainment Earth.