Body building for women came into its own in the late 1960's and early 1970's with such important early figures as Bev Francis, Rachel McLish, Lisa Lyon, Carla Dunlap, and Diana The Valkyrie (for more details on these figures, follow this link: http://keywen.com/en/FEMALE_BODYBUILDING).
The Ms. Olympia competition was first held in 1980 and was originally made up of contestants hand picked by the promoter of the contest, George Snyder. However, after 1984, contestants were no longer hand picked and instead had to qualify by placing in lesser contests throughout the year.
Female body building has gone through multiple transformations over the years, with the aesthetic changing from slightly muscular to extremely muscular to the 20% rule implemented in 2004 in which Jim Manion, the president of the National Physique Committee asked that the women decrease their muscularity by 20%. For more on his organization, see this website: http://www.getbig.com/articles/npc-hist.htm.
It seems that women in the early days of the sport were less bulky and smaller than subsequent female bodybuilders. Although after the call for the 20% decrease in muscularity in 2004, it seems that size slowly crept back up again so that today's female body builders are often bulkier and heavier than their early 1980's counterparts such as Rachel McLish and Lisa Lyon.
There have been some controversies regarding female bodybuilders and Playboy magazine. Historically there has been somewhat of a double standard among the public in terms of the perception of female body builders and their own sense of their femininity. While many women have felt it appropriate to translate their bodybuilding careers into careers with Playboy and other magazines, some feel this is an affront to the purity of the sport and the sense of empowerment that many women gain from watching and supporting the competitors.