After she was brutally beaten by her stepfather, 7-year-old Nixzmary Brown lay naked, weeping, and begging for her mother, but no one came to her aid or called for medical help until hours after she died, prosecutors said.

The girl’s stepfather has already been convicted of manslaughter, but prosecutors have now put her mother on trial for murder and other charges for allowing the vicious abuse to go on.

The trial has raised the question of whether mothers should be held to a higher standard than fathers at a time when traditional gender roles in the home are changing.

“In failures of care, mothers are held much more responsible, even when other individuals and agents play a role,” a sociology professor at the University of New Hampshire and the director of the Crimes against Children Research Center, David Finkelhor, said. “A good way of looking at whether the issue of bias was involved: If the gender roles had been reversed, would the outcome be the same?

“The things that men do, abandoning their families, the kids, very rarely are they reported or cited as perpetrators of neglect, unless they somehow are the primary caregiver,” Mr. Finkelhor said. “That’s not true with women.”

Prosecutors said that Nixzaliz Santiago had failed to protect her child in shocking fashion, and should be thoroughly punished. “This is about what she didn’t do,” the prosecutor, Ama Dwimoh, said of Ms. Santiago. “She failed her daughter miserably.”

Ms. Santiago has been charged with second-degree murder, manslaughter and reckless endangerment in the death of Nixzmary, though her husband, Cesar Rodriguez, has been convicted of manslaughter for delivering the blow that killed the little girl. She was so malnourished when she died that she weighed only 36 pounds — about half the weight of an average girl that age.

Ms. Santiago pleaded not guilty and went on trial last week. The killing hastened reforms in New York’s troubled child welfare agency and made Nixzmary’s name synonymous with child abuse.

Rodriguez dodged a murder conviction at his trial in February but was convicted of the lesser manslaughter count, with several jurors at Rodriguez’s trial saying a mother had a higher duty to protect her children than a father or stepfather. He received the maximum 25 years on manslaughter and four more years for additional lesser counts.

Ms. Santiago’s lawyers have argued that she was so traumatized and frightened by Rodriguez that she was incapable of helping Nixzmary. Attorney Sammy Sanchez portrayed Ms. Santiago as a loving but “unsophisticated” mother with a fifth-grade education who relied on men for support.

He also hinted that she had emotional problems, telling the Brooklyn jury of 10 women and two men how she once took a miscarried fetus home from the hospital in a jar and put it in her bedroom.

Nixzmary died in Jan 2006 of a vicious blow to the head while being punished for stealing yogurt from the fridge. Ms. Santiago reported finding the child unconscious in the family’s three-bedroom apartment.

Investigators discovered she had been a virtual prisoner, confined to a room with dirty mattresses, a broken radiator, a wooden chair to which she was bound with a rope, and a litter box she was forced to use instead of a toilet.

There had been warning signs for years before Nixzmary’s death. School employees had reported that she had been absent for weeks the previous year. Neighbors noticed unexplained injuries and noted the child appeared under-fed, though Mr. Sanchez has said she was just small for her age. Child welfare workers had been alerted twice but said they found no conclusive evidence of abuse.

Ms. Santiago’s trial began with Sergeant Erick Nolan, who first responded to the scene, testifying as gruesome photos of a beaten, emaciated Nixzmary were shown to the jury. Sergeant Nolan testified during Rodriguez’s trial as well.

Attorneys for both sides will have a challenge based on the outcome of the previous trial and Rodriguez being acquitted of the most serious charges.

“The prosecution has the opportunity to learn from its mistakes. They can see how a previous theory of the case was accepted or rejected by the jury and alter their approach to the case if necessary,” a former Manhattan prosecutor who is now a defense attorney, Jeremy Saland, said.

Mr. Saland said the defense is contending with possible preconceived notions as to the defendant’s guilt.

“The defense attorney must aggressively fight an uphill battle to make sure a fair and impartial jury is empaneled despite the terrible nature of the crime and the publicity it received,” he said.