One of the judicial contexts in which judges appoint psychologists as legal experts is that of parental conflict and decisions regarding minor children. Insight into family dynamics, assessing their characteristics and potential impact on children's health, and providing the judge with information to decide on child custody is a professional activity with strong ethical, as well as scientific and methodological, value. Observation, interviews, and any psychodiagnosis of adults and minors must be conducted not only in accordance with the methodology indicated by scientific literature and ethical guidelines, but also taking into account the impact this assessment and the resulting decisions have on people's lives, especially on the protection of minors and their needs in relation to their stage of development. Psychologists must have specific training in forensic psychology that allows them to operate in accordance with the laws and practices of the judicial context and to maintain the scientific and methodological independence of their discipline. Meeting and assessing individuals in this context requires ethical behavior that is respectful toward those being assessed, with attention to identifying both critical issues and resources, and proper positioning in one's professional role, both as a judge's expert and as a lawyer's expert. Some particularly important or timely points will be analyzed, such as the promotion of interventions for families and minors (mediation, parental coordination), and the specifics of assessment in transcultural families and same-sex families.