This population would most likely be declined.
The tendency described, in which couples decide to delay the age at which they have children to focus on suceeding in their professional careers first, causes that they do not use most part of their fertile lives. Therefore, when they decide to have children, they will be physically more limited, and also they will have time for a lower number of children than before.
It is also possible that the focus set on work continues and they decide not to be parents at all.
