The pop signer toured a hospital for HIV-infected children in eastern Ukraine on Saturday as part of a charity project and said that he and his male partner David Furnish wanted to adopt an HIV-infected boy named Lev.
But the country's Family, Youth and Sports Minister Yuriy Pavlenko told The Associated Press that adoptive parents must be married and Ukraine does not recognize homosexual unions as marriage.
John and Furnish, his longtime partner, tied the knot in 2005 in one of the first legalized civil unions in the United Kingdom.
Pavlenko also said John was too old. The singer is 62 and Ukrainian law requires a parent to be no more than 45 years older than an adopted child.
"Foreign citizens who are single have no right to adopt children ... and the age difference between the adopter and the child cannot be more than 45 years," Pavlenko said. "The law is the same for everybody: for a president, for a minister, for Elton John."
John gave Lev a big kiss at the orphanage in Makiyivka.
"I don't know how we do that, but he has stolen my heart. And he has stolen David's heart and it would be wonderful if we can have a home," John said.
Even before the decision, CBS News Correspondent Elizabeth Palmer reports that critics were saying this was just another high-profile adoption, like Madonna's and Angelina Jolie's -- celebrities picking out orphans as designer trinkets.
Little is known about Lev, Palmer adds, except that his mother is alive (although she has never visited), and that he has a brother in the orphanage.
Pavlenko said Ukraine was grateful for the singer's charity work and expressed hope that his desire to adopt Lev would spur the domestic adoption of more children with health problems, which is still rare in Ukraine.