"A species is often defined as a group of organisms that can reproduce naturally with one another and create fertile offspring"
To be a part of a species, You must be able to produce fertile offspring. If a supposed homo sapien could not produce fertile offspring with another homo sapien, At least one of the parents are not part of species H. Sapiens.
Since they can't produce fertile offspring they are technically not human.
Personally i think that people who can't even produce normal kids should be exterminated as to help future generations. Artificial selection is required here. Just my opinion, Though. Anyway, TLDR no, They are not part of the human species