Thanks for posting your query at DoctorSpring.com
Let me clarify your doubt.
The fact is this.
Every female is born with a fixed number of eggs.
The union of sperms and eggs leads to pregnancy.
In males, sperms are constantly produced till age of 70 or more.
In females, eggs are fixed at birth, and each cycle, during menstruation , eggs are used up.
With age, the egg capacity falls.
Egg quality also falls.
This effect is more marked after the age of 30 in females.
If she conceives before that, there is no problem.
I hope the situation is clear.
All the best
Please feel free to discuss further.