Goofs

Genetic evidence now shows that Neanderthals were the ones whose hair ranged from being either blonde or red, whereas a Cro-Magnon's would have been far more darker in color.

Although Ayla is an early Homo sapien living with Neanderthals, she has shaved legs & armpits.

At the meeting of the clans Ayla meets a man with blue eyes. The mutation to the ACO2 gene that results in blue eyes occurred somewhere between 6 and 10 thousand years ago. This is long after the 35000 years ago given as the time of the movie.

With the film's setting taking place somewhere in prehistoric Europe, realistically, it would've been more appropriate for The Clan's little hunting party to have gone after steppe bison, since there was a literal abundance of them roaming all around the European region during this time period, instead of the musk oxen that were featured inhabiting the woodland area.

Throughout the movie, Pamela Reed (who played Iza) sported long, clean, beautifully manicured fingernails - not a likely feature on an active female Neanderthal.