Investigating knowledge, attitude, and practice regarding the health risks of consanguineous marriages in Saudi Arabia: a cross-sectional study

Objective: This study aimed to study knowledge, attitude, and practice regarding the health risks of consanguineous marriage (CM) among the population in the Western region of Saudi Arabia. Methods: A cross-sectional study was conducted among a total of 1,789 adults aged 18 years and above, residing in the Western region of Saudi Arabia, from June to July 2025, using a snowball sampling technique. An online questionnaire was designed based on a literature review. Results: The participants were predominantly females (70.3%), aged 21-30 years (42.3%), and university educated (58.0%), with 20.4% working in medical professions. Of the 762 who responded to the consanguinity question, 33.2% reported being in a CM, mostly with the first cousin (25.2%). Overall mean knowledge score was 73.4% ± 26.4%, with 80.8% scoring above 50%; mean attitude score was 70.1% ± 9.1, with 98.4% scoring above 50%. Knowledge gaps were identified in awareness of premarital screening components (26.4% correct) and availability of premarital whole exome sequencing (51.6% correct). Female gender, younger age (18-20 years), university or high school education, and healthcare employment were independently associated with higher knowledge scores (p < 0.05). Attitudes were uniformly positive toward genetic screening but varied toward CM. In practice, 60% reported avoiding CM if screening results were incompatible. Conclusion: While general knowledge and attitudes toward genetic screening were favorable, substantial educational gaps persisted, particularly regarding available testing and residual genetic risk. This highlighted the need for targeted public health education and campaigns for older, less-educated, and non-healthcare populations.