California typically has tighter housing controls than the Federal government and most other states with regards to housing.

Here is the page delineating what qualifies as discrimination and what the exceptions are.

http://www.dca.ca.gov/publications/landlordbook/discrimination.shtml

basically there are 2 exceptions:

-Boarders:
If you rent out a single room to a single boarder in an SFR (including attached I think) then you are not subject to antidiscrimination rules.
That does not extend to renting out multiple rooms or to multiple people.
Just for a family renting out one room of their house.

-Roommates:
If you are going to share common areas (kitchens, bathrooms) you can express a gender preference.

There is also senior housing.