The genetic fallacy is also known as the fallacy of origins. A claim is accepted to be true or false based purely on its origin or history.
The origin of a Claim is presented
The Claim is declared true (or false)
Examples
X is a politician
He is corrupt
Here we conclude he is corrupt because his origins are In politics
He is from India
He doesn't know how to use a fork
Most Indians don't use forks. Since he originated from India, It is assumed he doesn't know how to use a fork.
Ayurveda was developed 2000 years back
It can't be scientific
Since Ayurveda originated 2000 years back - it can't be scientific. There is also a implicit assumption in this argument - that anything originating 2000 years back cannot be scientific.
All these are fallacies because the claims are made based on the origin, and not on an examination of the specific facts and context.