The penalty phase of the Scott Peterson trial is underway as jurors hear testimony from friends and family members from both sides. Attorneys for the defense have called 28 witnesses to testify on behalf of Scott Peterson, and another 10 are expected to take the stand before the jury begins its deliberation on Thursday.

At stake is whether the 32-year-old former fertilizer salesman will receive life in prison without parole or the death penalty. For days, jurors have heard glowing testimony from friends and family about Peterson's childhood, his good deeds, and how a death sentence would catastrophically impact his family.

Scott Peterson was convicted on November 12, 2004 of murdering his pregnant wife, Laci, and the fetus she was carrying. The same jury that convicted him is now tasked with deciding his fate. And if past death penalty cases are any guide, the jurors of this well-publicized trial will have to wrestle with serious moral and legal issues as well as any lingering doubts about Peterson's guilt before making their final decision.

While deliberating Peterson's sentence, the jurors will have to weigh several factors, including aggravating factors (those that make the crime particularly terrible) and mitigating factors, such as testimony regarding the defendant's good character. The fact that Peterson was convicted of two murders automatically limits his sentencing options to life in prison without the possibility of parole or the death penalty.

Does Scott Peterson deserve the death penalty?

Interestingly, Peterson was not convicted of a double count of first-degree murder. The jury found him guilty of premeditated murder only in the death of his wife, Laci, but not in the death of his unborn son. This decision could indicate some hesitancy on the part of the jury to deliver a first-degree murder conviction in the case of a fetus, although it has been done in the past. In California, there are currently three men on death row because a fetus perished during a murder.

Another possibility is that the jury wanted more "emotional" leeway when deciding Peterson's fate. Although it is legally possible to sentence Peterson to death with only one count of first-degree murder, two counts of first-degree murder would make the death penalty that much harder to deny.

In 2001, a California jury sentenced Todd Garton to death for a similar crime with a different set of charges. Todd Garton was also a philandering husband found guilty of hiring a hit-man to kill his pregnant wife. But unlike Peterson, Garton was convicted of two first-degree murder charges. In Garton's case, it took all of 70 minutes for the jury to decide on the death penalty.

There is also the possibility that the jury in the Peterson case will be unable to reach a unanimous decision, in which case the prosecutors can either convene a second jury to decide the sentence, or allow the judge to determine the punishment. A judge, however, is not permitted to impose a death sentence without the jury's recommendation, meaning Peterson would automatically receive a life sentence.

Death penalty sentences are still relatively rare in California. In 2003, a total of 22 persons received the death penalty, bringing the total number of people on death row in California to 639. Whether Scott Peterson joins them, or spends the rest of his life behind bars may be clear by week's end.