Brady Bunch producer Sherwood Schwartz once said that Susan Olsen-a.k.a Cindy Brady- was the only cast member who had the job at first sight. And indeed, "the youngest one in curls" was a cutie, although her lines on the show were sometimes downright lame. Olsen herself even complained about how "dumb " Cindy was, but no one can deny that in the early days of the Brady Bunch, Cindy's cuteness factor stole the show.

http://collectingtokens.files.wordpress.com/2007/09/brady_cindy1.jpg

http://www.associatedcontent.com/article/5467630/the_most_adorable_child_stars_of_all_pg2.html?cat=49

It must have been the curls.