Dolly was put to death Friday, after premature aging and disease raised questions about the practicality of cloning.
"I think it highlights more than ever the foolishness of those who want to legalize (human) reproductive cloning," said Alan Colman, one of the scientists behind Dolly's birth in 1996.
"In the case of humans, it would be scandalous to go ahead given our knowledge about the long-term affects of cloning," Colman said.
Scientists decided to end Dolly's life at age 6 - about half the life expectancy of her breed - because a veterinarian confirmed she had a progressive lung disease, according to the Roslin Institute, the Scottish lab where she was created and lived.
Last year, Colman was lured away from his post as research director of Edinburgh, Scotland-based PPL Therapeutics, which helped clone Dolly. He considers himself one of Dolly's "godfathers."
"Obviously it is the end of a sort of era," Colman said. "I was very fond of the old girl."
Dolly was the first mammal cloned from an adult stem cell. Since then, whole herds of cattle, sheep, pigs and other animals have been cloned.
Colman moved to this Southeast Asian city-state last year to set up a laboratory for an Australian-based venture.
His move here was a coup for Singapore, which has been aggressively trying to promote its biotechnology industry. The city-state is an investor in his new company, ES Cell International.