Question

In a nuclear reaction, the parent element is always radioactive.

Answer 1

Hydrogen to be more precise protium which is an isotope of hydrogen containing one proton and one electron. It is considered to be very stable which explains it's abundance everywhere. However under extreme conditions like in the sun, it undergoes nuclear fusion to form helium. So in conclusion, under normal circumstances Protium is considered to be very stable however under extreme circumstances it is radioactive. Does that answer your question?