I began investigating potential investigating possible environmental causes of the cognitive ability gap in another post. I argued that common environmental explanations – test bias, schooling, socioeconomic status, and societal racism – failed to explain the gap. Because common environmental explanations fail, it may prove useful to consider non-environmental (i.e. genetic) explanations of the gap. I will perform this task in this post. First, I will clarify the meaning of estimates of the heritability of intelligence. Next, I criticize some common poor arguments against genetic explanations of the gap. Then I will consider some arguments for a genetic explanation of the gap that are related to the heritability of intelligence. I conclude that such arguments are not sufficient to make any conclusion either way about the cause of the gap. I end by detailing the kinds of direct data that should be used to confidently conclude whether and to what degree the cognitive ability gap is due to genetic differences.