I have a question,in California,I am finding that if a sperm donor is used and he is known and without the use of a doctor than he is still the father,now my qusetion is this can a the known donor sign off all legal rights after child is born to have partner adopt?

Yes it is simple to have them sign the rights away after the child is born, would be just like a step parent adoption. Very simiple.
I would have the attorney do a contract stating what is to happen, and have them so the paperwork, But this is very common.

Thank you for this answer.It helped us.