When did British royals decide marrying first cousins wasn't a good idea?

Question

I know Victoria and Albert were first cousins, but several of heir grandchildren and great grandchildren also married first cousins. However, no King or Queen since V & A has married a close relative.

Answer 1

u answered your own question lol.

Answer 2

When they found out it was disgusting and knew it would cause inbreeding which has already happened to the royals.

Answer 3

Simple answer: World War I intervened, stripping many European monarchs of their titles and the Tsar and his immediate family of their lives.  

Long explanation: Of course, Edward VII, Queen Victoria's son, was related to most of the crowned heads of Europe:  Kings Charles I and Manuel II of Portugal, King Ferdinand of Bulgaria, and Prince Ernst Augusta, Duke of Brunswick-Luneburg, were (first) cousins.  Kaiser Wilhelm II, Tsar Nicholas II,  Grand Duke Ernst Ludwig of Hesse and by the Rhine, and Grand Duke Carl Edward of Saxe-Coburg Gotha were nephews.  Queen Victoria Eugenia of Spain, Crown Princess Margaret of Sweden, Crown Princess Maria of Romania, and Russian Empress Alexandria Feodorovna were nieces.  King Haakon VII of Norway was a son-in-law, and King George I of the Hellenes and King Frederick VII of Denmark were brothers-in-law.  

After World War I, relatives of the British Royal Family who fought on the Axis side were simply cut off by an Act of Parliament in 1919.  After the Bolshevik Revolution, the Tsar and his family were left to perish in Russia.  In addition to the Russian Royals,  the monarchies of Austria, Germany, Greece, and Spain fell after the First World War.   Even so, Queen Elizabeth is a third cousin of Prince Phillip of Greece through Queen Victoria and a second cousin once removed through Christian IX of Denmark.  For that matter, the great grandmother of Camilla Parker Bowles, Alice Keppel, was Edward VII's last mistress (old customs die hard).

During the Roaring Twenties and turbulent 1930s, George V's children broke the pattern of marrying distant royal relatives.  Edward VIII, the Duke of Windsor, married Mrs. Wallis Simpson, an American socialite and divorcee, and his younger brother Albert, later George VI, married Lady Elizabeth Bowes-Lyon, the daughter of a Scottish Earl.

Answer 4

I think  Prince Charles is a good example of that.