This bill, titled "The Family Doctrine," establishes a legal defense for individuals who use force against perpetrators of sex crimes against minor family members or household members. It introduces a new section that allows a person to justify the use of force if they reasonably believe it is necessary to defend a child victim from imminent unlawful force or to prevent imminent death or serious bodily injury to that child. The bill specifies that the use of deadly force is only justified under certain circumstances, particularly if the perpetrator has previously committed a crime against the child victim.

Additionally, the bill defines "child victim" as a member of the person's immediate family or household who is under 18 years of age. It also includes a codification instruction indicating that the new provisions will be integrated into Title 45, chapter 3, part 1 of the Montana Code. This legislation aims to provide legal protection for individuals acting in defense of vulnerable minors within their families or households.