I believe that Charity loved Sylar, but she loved herself more. Going through the steps of giving up a child for adoption has got to be excruciating, and I do believe, for what ever reason, she did want involvement in Sylars life, but on her terms. Christine offered her that opportunity, and to most of us it seems obvious that Tina would not be a good choice. But everything is relative, to Charity, who abandons children, doesnt work, lives like a gypsy, and has had problems with meth-Tina seemed like an upstanding citizen. As for whether Charity was on drugs when Sylar was born I cant say for sure, but I thought I had read that one of her previous babies was born with pot in his system. That tells me that its not beyond the realm of possibilities, but knowing this, wouldnt the state have tested Sylar?