Jehovah's Witnesses are strict about who can be a member. They only count people as members if they are baptized (or getting ready to be baptized) and they preach each month.. Like other Christian groups, they believe baptism represents devotion to God and their promise to live by his teachings. Unlike some Christian groups, Witnesses are not baptized as babies. There is no set age required for baptism, but they believe baptism should be a choice made by someone who is willing and understands what it means. However, it is common for young children and teenagers to be baptized.