Scientists on Thursday formally announced the start of a 10-year project aimed at vastly improving the ability to chemically manufacture DNA, with one of the goals being to synthetically create an entire human genome.

Plans for the project, which leaked last month, have already set off an ethical debate, because the ability to chemically fabricate the complete set of human chromosomes could theoretically allow the creation of babies without biological parents.

Some critics also objected to the secrecy surrounding a meeting to discuss the project at Harvard Medical School in May. The organizers said they avoided publicity so as to not jeopardize publication of the proposal in a peer reviewed scientific journal. The publication occurred on Thursday by the journal Science.

The authors of the proposal said that the ability to fabricate huge stretches of DNA would allow for numerous scientific and medical advances. It might be possible to make organisms resistant to all viruses, for instance, or make pig organs suitable for transplant into people.