It would 100% be 40 to 50 years old.
The component of DNA that became the source of this information is : the base
The backbone of our DNA carries four type of bases which each could contain unique sequences
These unique sequences of the four bases are the one that encodes the information.
Density. Density is the measurement of how much matter is in a substance
The child would have a 1/4 chance of being 100% normal