As matching skills advance, recognisable differences register and slowly evoke comment. Although intelligence, stimulation by older siblings, or being very experienced can all speed up the process, 6-7 years is about the age at which average children start making deductions and sometimes faulty conclusions. This was the age at which the two sisters commented on the difference in their genitalia. Between 7 and 11 years, the average mind starts to range a little more but is still not thinking in adult terms. Deductive ability improves and the making of correct connections is now possible.
Many adults have no clear concept of internal anatomy.
The matching idea of 'shaping up' like the other girls, even though used with the strange phrase 'hormonal replacement', aided the concept of being like everybody else, so important in preteens as well as to teenagers. Familiarity with a medical term was useful, though understanding would come later. By the time that the illustrative film actually arrived, the girl was almost at the perfect age for viewing it. Looking back into embryological life and imagining the body's internal schema was now comprehensible with visual aids, but would have been difficult without them. Her forward ranging question about the length of treatment was again a mark of her age group, mental gymnastics having now been acquired.