Credit for the first organized cheer is attibuted University of Minnesota student named Johnny Campbell, who in 1898 encouraged the crowd to shout, “Rah, rah, rah! Sku-u-mar, Hoo-rah! Hoo-rah! Varsity! Varsity! Varsity, Minn-e-so-ta!”. Soon after, a yell-leader squad of six male students was formed and other universities soon followed.
Women joined cheerleading in the early 1920′s and began to dominate the sport in World War II when few men were involved in organized sports. It was at this time that gymnastics, tumbling, and megaphones were incorporated into popular cheers, and are still used today.
Current estimates show that 97% of cheerleading participants are female. However, at the collegiate level, it is a co-ed sport with 50% of cheerleaders being male. (Wikipedia)