Repulsion or Napalm Death who is the father of grindcore?

There has been debate on who the father of grindcore is. Some argue that it's Repulsion or that it's Napalm Death? What do you guys think?

I don't know, I discovered Napalm Death after talking to their drummer in a record shop and from there went to Heresy, Repulsion and Unseen Terror. I wouldn't like to guess who was the first band to be officially considered 'Grindcore' as so many of the punk bands were getting faster and faster.

I heard Napalm Death was, but I could be wrong.

Napalm Death formed first, but Repulsion had an album out first. So in that regards, I guess it would be debatable.

Wasn't in Siege? Or were they more hardcore? Repulsion and Napalm Death were both influenced by them.