My child is an atheist. How did this happen when I raised her as a Hindu Brahmin?

your child grew up and met the world, that is all that happened. i am quite glad that your child has an independent mind that can reason for itself. do not be disheartened please. whether your child is an atheist or not, the more important thing is to make sure your child is a compassionate and caring human being. if she didn't find a reason to believe in a particular religion or god, it is entirely her choice. let her find her life and her beliefs in her way, while you follow yours :)