This is what a friend of mine said:
When there's human offspring, it will look a rough 'medium' between the two parents, with it sharing features from the two. well if the offspring of one set of parents has sex with the offspring of another set, the outcome becomes a 'medium' of those two. So the range from what we shall call 'completely average looks' (a hypothetical state of the average of everyone in the world, which is acceptable as we're looking at a process of millions of years) becomes less and less the further into the future we go. Eventually, there is almost no range between people and 'completely average looks'.
In summary: take the hypothetical average of everyone in the world, and because the offspring of two people is a slight mixture of those two people, they are a tiny bit closer to the hypothetical average of everyone in the world, which means that eventually people will be getting closer and closer to this average, so will one day look the same. So he's suggesting that slowly people will become more and more similar.
My argument is that, although this baby may be that tiny bit closer to the overall average, they're new look has effectively altered the average, meaning that they aren't actually getting closer to the average.
I'd like an opinion and flaw from some experts, such as yourselves, so please...