Updated

Potential jurors in the retrial of a Texas mother who claims madness in the bathtub drownings of her five young children challenged the legal definition of insanity in court Thursday.

Several of the 120 potential jurors being questioned for the Andrea Yates case said they disagreed with the legal definition.

As in her first trial, Yates has pleaded innocent by reason of insanity in the June 20, 2001, drowning deaths of her children. Her earlier conviction was thrown out because of erroneous testimony.

Yates, 41, stood Thursday as her defense team was introduced to the jury pool, smiled slightly and quietly said, "Good morning," before returning to her seat. She sat quietly throughout the morning, watching state district Judge Belinda Hill and the jury pool.

Her attorney, George Parnham, has described Yates as "scared to death" and has said that her mental condition deteriorates around the anniversary of the drownings.

Texas' legal definition of insanity states that the defendant did not know the conduct was wrong at the time because of severe mental disease or defect.

Some of the potential jurors asked for legal definitions of "severe" and "wrong," but the judge said she could offer none.

About 20 potential jurors said they had already decided Yates was legally insane without hearing any evidence; three dozen others said they couldn't be impartial because of what they had already heard about the case.

Parnham argues that his client is mentally ill and that severe postpartum psychosis prevented her from knowing that drowning her children was wrong.

Prosecutors maintain that Yates doesn't fit the insanity definition. They have said they planned to present the same evidence of how Yates killed the children after her husband left for work and before her mother-in-law arrived to help care for them, and how Yates called 911 to report the crime.

Jury selection was expected to last through Friday, and opening statements in the case were set for Monday.

Yates' earlier conviction had been thrown out because of erroneous testimony from a key prosecution witness, a psychiatrist who was a consultant on the "Law & Order" television series.

Dr. Park Dietz had told jurors that an episode depicting a woman who drowned her children in a bathtub — and was acquitted by reason of insanity — aired before the Yates children were killed. Attorneys later learned that no such episode existed.

In both trials, Yates was charged only in the deaths of 6-month-old Mary, 5-year-old John and 7-year-old Noah. Her sons Luke, 2, and Paul, 3, were also drowned in the family's bathtub that day.

If convicted of capital murder, Yates will be sentenced to life in prison. The first jury rejected the death penalty, and prosecutors cannot seek death again because they did not find new evidence.