The South Korean cloning scientist accused of faking his stem cell research has gone on trial in Seoul, charged with fraud and embezzlement.
Dr Hwang still has many supporters
Hwang Woo-suk is also accused of using government and other grants for private purposes and violating laws on bio-ethics.
Last year, his most-heralded research - producing stem cells from a cloned human embryo - was found to be fake.
If convicted, Dr Hwang faces at least three years in prison.
His lawyer said in opening remarks that Dr Hwang had believed his laboratory's stem cell findings were genuine until he was faced with evidence that they had been faked.
Dr Hwang has in the past blamed junior researchers for faking the data.
Supporters of the scientist gathered outside the court before the trial began and shouted slogans, the Associated Press news agency reported.
Fall from grace
Dr Hwang, formerly a professor at Seoul National University, had been viewed as a national hero for his apparently ground-breaking research on stem cells.
Feb 2004 Hwang Woo-suk's team declare they have created 30 cloned human embryos and extracted stem cells
May 2005 Team says it has made stem cell lines from skin cells of 11 people
Nov 2005 Hwang apologises for using eggs from his own researchers
15 Dec 2005 A colleague claims stem cell research was faked
23 Dec 2005 Academic panel finds results of May 2005 research were fabricated
10 Jan 2006 Panel finds 2004 work was also faked
20 March 2006 Hwang sacked from SNU
12 May 2006 Charged with fraud and embezzlement
He had claimed in the journal Science to have created a stem cell line from a cloned human embryo, later publishing a second paper in which he said his team had extracted material from cloned human embryos that identically matched the DNA of 11 patients.
His "progress" appeared to bring researchers closer to the point where they could offer personalised cures, using tissue grown from embryonic stem cells to repair damaged organs or treat diseases like Alzheimer's.
But in December a panel at Seoul National University found that his research had been "intentionally fabricated". In May, prosecutors brought charges against him and his team.
He is accused of accepting donations worth 2bn won ($2.1m, £1.14m) on the basis of his research, and of embezzling a further 800m won ($831,000, £451,000) in research funds.
He is also alleged to have bought human eggs for his research work, which is a violation of South Korea's bio-ethics law.
He is being tried with five colleagues who are facing similar charges.