Is it possible that there are two people in the world who belong to a different species?
At the beginning, the population of the parents who we are talking about should be made more specific. Let's limit it to adult, healthy individuals (let's skip pathologies, various kinds of random body injuries, personal sexual preferences and close relatives).

From the descendants group, let's also exclude children who would die from random causes, body injuries (unintentional :-( and intended :-((( ), genetic diseases, etc.In addition to the genetic variation (A global reference for human genetic variation), epigenetic variability (Worldwide patterns of human epigenetic variation) should also be taken into account.

If we give the most popular definition of a species (and there are very many of them), as individuals capable of giving fertile offspring, of course all humans belong to one species. Contrary to popular opinion, we are similar to one another like drops of water.