During March 2008, O'Brien highlighted the issue of the Human Fertilisation and Embryology Bill being debated in Parliament, denouncing the government for a "monstrous attack on human rights" through its "evil" endorsement of "Frankenstein" experiments. Some scientists suggested that he intentionally used inflammatory language to stir up opposition to the bill; others argued he was sticking up for morals and forced the Government to allow MPs to vote freely on the issue. (Gordon Brown had originally imposed a three-line whip on Labour MPs, meaning they had to back the bill, regardless of personal convictions.)