The additional segmentations Age and Gender has been added to the Twitter connector.
These are two separate fields and are not available in Twitters API from the same segmentation. If you need to segment your data by both Age and Gender, then you need to connect the same ad account twice, selecting one segmentation for each Twitter data source.
Bear in mind that connecting the same ad account more than once will likely lead to some metrics being double-counted. You can read more about how to tackle this in the article Connect the same source twice, with different dimensions.
You can read more about what fields are available in the article What data can I get from Twitter?