Circadyan Rythms: Girls Prefer Evening to Morning Schedules (true?)

On a previous post, I wrote about the difficulties I have when trying to work at night, and I presented some links that suggested that there are health risks on shift work and night work. Now after reading this article, I realize that I might be wrong, because according to research at Stanford (cited by Dr. J. Gumbiner), pubescent matured girls prefer evening to morning schedules (Carskadon, 1999). Perhaps because of that their sleepover parties?
References.- The Teenage Mind, by Jann Gumbiner, Ph.D. - Carskadon, M. A. "When Worlds Collide: Adolescent Need for Sleep Versus Societal Demands, " Phi Delta Kappan, Vol. 80, No. 05, Jan. 1999, pp.348-353.