說到歐洲王室近親聯姻，估計最有名的是那個遍布歐洲王室們的血友病，和末代沙皇的倒台，太子就血友病

剛才再去隨手google一下，用"inbreeding depression in european monarchies"，出來好多

The Role of Inbreeding in the Extinction of a European Royal Dynasty

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664480/

Inbreeding Among Royals: 14 Monarchs Who Experienced the Side Effects of Incest

https://www.sciencetimes.com/articles/24610/20200107/inbreeding-among-royals-14-monarchs-who-experienced-the-side-effects-of-incest.htm

從google來看，覺得歐洲王室的近親結婚從政治角度有道理，從生物學上來說是有挺多負麵影響的