Three are parents. Three have relatives who struggle with a mental illness. Five live on the Upper West Side of Manhattan.

They are among 12 jurors and six alternates ready to hear the case of a nanny accused of stabbing to death two young children in her care in an affluent part of the neighborhood six years ago.

The trial of the nanny, Yoselyn Ortega, who is mounting an insanity defense, was scheduled to begin on Thursday in State Supreme Court in Manhattan with opening statements from prosecutors and defense lawyers. But it is the expected testimony of Marina Krim — who arrived home with her third child to find her two other children bloodied and dead in a bathtub and their nanny slicing her own neck — that will undoubtedly sear the minds of everyone in the room. Jurors may also have to contend with gruesome crime scene photos.

“If you don’t get emotional during this trial then maybe you need to check your pulse,” Justice Gregory Carro said in response to one prospective juror’s question about her ability to be impartial given the emotional nature of the case. He said he did not expect jurors to be robots.