while the age at which Americans become parents

[puttukoni8]

Problem Source - Foundations of GMAT Verbal book : Chapter 6 Drill 6.2 Question 4 says -

While the age at which Americans become parents has been steadily rising over past
decades, most young people still say that parenthood is an important milestone in
life, much as it was for their own progenitors.

My doubt ( with all due respect to Problem/Content creator and to whole Manhattan team) -
I am curious if word 'it' present in last clause of sentence is not fully right.

My Reasoning -
As I have read in SC book - pronoun chapter - that It, they, them refer to same copy; while only 'that or those' refer to New copy. In given problem, pronoun 'it' is undoubtedly pointing to parenthood; however, pronoun 'it' is pointing to the same copy of parenthood.
I think it should point to new copy of parenthood since progenitors' parenthood and young people's parenthood can not be the same copy.
I think we should use 'that' instead of 'it' in given sentence.

Kindly guide me. Kindly let me know if I am going wrong anywhere.

Thanks in advance
Mohit

[RonPurewal]

parenthood is still parenthood.

another example:
Your face has changed a great deal since the last time I saw it.
(your face is still your face, even though it has changed.)