Years ago, in Spain, my little cousin was denied baptism because his parents were not married in the Catholic church (the mom was Lutheran). Since a baptism certificate was then necessary for just about anything in Spain, beginning with registering for kindergarten, the parents agreed to get married again. Then it turned out that no priest would marry them as long as the mother was Lutheran, and she refused to convert just to go along. Eventually a priest married them in the sacristy and a few days later the boy was baptized.
What about Christians who don't believe in infant baptism, and non-Christians?