The latest Sims update makes all CAS assets available to both genders, male and female. The Sims dev team did confirm that existing CAS CC will function as normal. However, this means that you will have to update CAS CC for it to be available to both genders. Thankfully, The Sims devs released a guide explaining how to do so.
The core CAS change is that the UI no longer uses a part’s gender flag to determine which options show up for male and female Sims. Sex differentials are only used to tell the engine what body geometry the item was authored for. Three new options affect CAS behavior: physical frame, clothing preference, and gender (feminine or masculine). There are a few exceptions to these rules. For example, a male Sim with a female frame uses female geometry but does not have full breast control, and only male Sims can have beards.
The CAS Part Resource has been updated with a few key changes. Firstly, the ‘feminine’ and ‘masculine’ tags, which controls whether or not the item shows up in the respective filter.Items can also be restricted for the opposite frame or gender. There’s also an ‘opposite gender and fallback part specification.’ The opposite gender part takes priority over the fallback part. If the item is not compatible with the Sim because of frame or gender restricts, than it will use the rule specified in these fields. Read more about these specifications here.
Download the attached document and for more detailed instructions on CC behavior, and check out the latest patch notes for more information about what's in the CAS update.