Women first appeared in the modern Olympics in Croquet at the 1900 Olympics. 22 women competed in this the second modern Olympics in the sports of Croquet, equestrian, Golf, Sailing and Tennis,
Hélène de Pourtalès (Sailing), Charlotte Cooper (Tennis, one in singles and one in mixed doubles) and Margaret Ives Abbot (golf) won the first gold medals as female participants in these Olympics. As Ed mentions golf and tennis were the only competitions where women competed separately.