Scientists are now contemplating the fabrication of a human genome, meaning they would use chemicals to manufacture all the DNA contained in human chromosomes.

The prospect is spurring both intrigue and concern in the life sciences community because it might be possible, such as through cloning, to use a synthetic genome to create human beings without biological parents.

While the project is still in the idea phase, and also involves efforts to improve DNA synthesis in general, it was discussed at a closed-door meeting on Tuesday at Harvard Medical School in Boston. The nearly 150 attendees were told not to contact the news media or to post on Twitter during the meeting.

Organizers said the project could have a big scientific payoff and would be a follow-up to the original Human Genome Project, which was aimed at reading the sequence of the three billion chemical letters in the DNA blueprint of human life. The new project, by contrast, would involve not reading, but rather writing the human genome — synthesizing all three billion units from chemicals.