FA Bans Women
In 1921 the FA made the decision to bar women from playing on all affiliated grounds, deeming women playing soccer unsuitable and unsafe based on the advice of ‘medical experts.’ Many believe that this ban was actually due to envy of the large crowds that women's matches attracted, and because the FA didn’t appreciate that they had no control over the money made from the women's game. Women didn’t return to the playing field in a significant and official capacity for about 50 years.

The FA were not the only ones to ban women from playing in some capacity. France followed suit in 1932, Norway in 1931, Brazil in 1941, and West Germany in 1955.
Sources:
Girls Soccer NetworkThe GuardianHistory ChannelFootball and the First World War