Vaughn and Moore suggest jury instructions that emphasize physical circumstances. The defense attorney may want to note, for example, that women are not usually as able or trained to defend themselves as men are and that other factors such as pregnancy may be involved. Lyson and Morrison recommend that jury instructions emphasize the nature and length of the defendant's relationship with the deceased, the history of physical abuse between the couple, and the defendant's socioeconomic status. Lawrence and Kugler propose jury instructions that focus on the issue of statements or confessions made to police by battered women who kill, the appearance of danger, the reasonable pregnant woman standard in self-defense, evidence to be considered in self-defense cases when determining if a defendant's conduct was reasonable, the duty to retreat before using self-defense, and the legal principle that no one is required to retreat from the home in order to avoid being attacked. In general, jurors must be told that a person is justified in the use of force when such conduct is deemed necessary to defend against the imminent use of unlawful force.