when Sonny slept with Sam, he did not know that she was Alexis' daughter. I am not saying he wouldn't have had he known. Just that he didn't know at the time. After all, this is the man who slept with his son's GF.
I still remember Carly coming in and mocking him about sleeping with mother and daughter. As if she had any room to talk, This is the same woman who seduced her mother's husband. Of course, Sam seduced Ric when Alexis was battling cancer.
My objection is because I actually like Drew and Nina.