There's a new report type available for our YouTube connector: Age and Gender. With the new Age and Gender report you can see the Viewer Percentage by Age and Gender, on a per-video level. The Viewer Percentage metric is non-aggregatable and only available through this new report type. It's also worth to note that this report is subject to YouTube’s data anonymization. This means that, if a YouTube channel doesn’t have enough traffic, the report will not return any data.
You can read more about the data available from YouTube in this knowledge base article.