By implying that 11- and 12-year-old girls are “prepubescent”, you play into the hands of those who oppose vaccinating young girls against human papilloma virus (HPV) to prevent cervical cancer (Nature 477, 369; 2011).

Although the average age of first menstruation (menarche) was 12.8 years in the United States in 1968, this is becoming steadily younger (see, for example, S. E. Anderson and A. Must J. Pediatr. 147, 753–760; 2005). Also, as menarche comes quite late in a girl's progress towards full adult height and reproductive capacity, girls should no longer be described as prepubescent at ages 11 and 12.

A case could be made for scheduling vaccination against HPV at an even younger age — at the start of breast development, or around age 10, before a girl is likely to become sexually active.