Jeremiah Clayton Jones discovered that his former fiancée was pregnant just three weeks before the baby was due, when an adoption-agency lawyer called and asked if he would consent to have his baby adopted.

"I said absolutely not," said Mr. Jones, a 23-year-old Arizona man who met his ex-fiancée at Pensacola Christian College in Florida. "It was an awkward moment, hearing for the first time that I would be a father, and then right away being told, 'We want to take your kid away.' But I knew that if I was having a baby, I wanted that baby."

Mr. Jones has never seen his son, now 18 months old. Instead, he lost his parental rights because of his failure to file with a state registry for unwed fathers -- something he learned of only after it was too late.

Under Florida law, and that of other states, an unmarried father has no right to withhold consent for adoption unless he has registered with the state putative father registry before an adoption petition is filed. Mr. Jones missed the deadline.