You know that the genes which we have inherited/we inherit from our ancestors determine our quality of life and whether we are be successful or not.
That's an interesting and thought-provoking question. I've never been a big fan of the karma idea. Maybe because it calls to mind Eastern Mysticism, or something. But, I've never really noticed karma to be true, not in the way it's used in the US.
Really good things happen to bad people and bad things happen to really good people, so unless I'm misunderstanding the karma concept, I just don't see it as a reality.
I tell people, even though they often think it's crazy, that the impersonal forces of nature in this world, however they manifest themselves, have done more harm to people since time in memorial, and are far crueler, than any human has probably been to another, in a very broad sense and in terms of the universe as we know it. Why do children die of cancer in hospitals every day? Explain that one. Look at all the natural disasters that occur all the time. The world is so full of pain. Why? These are the questions I can't answer, but we can sure try to lessen those sufferings and help one another. That's why I posted that passage from Bertrand Russell's "A Free Man's Worship" last night, because it touches on this subject in a non-religious way and raises these very issues of how hard life really is and how we should help one another and be good to one another whenever we can.
You don't want to hear this, but karma.
Not the karma like "you were Hitler before, so now you are a poor, abused kid in a poor, desolate country". More like....if you are learning what it means to be human, and if you were always good-looking, rich and comfortable, how would you experience the vast range of human experience? You wouldn't be able to. You would have a very narrow viewpoint because your experience would be very narrow. The total experience of being a human would be lost on you. You would have been better off staying in heaven.
Problems challenge us to grow. Just look at the handicapped athletes at the Special Olympics. They are far more impressive....and far better athletes... because they have to overcome themselves and their situation. It's horrific to see what other humans suffer through, and that we will suffer through as well at some point....but that's the whole idea: being human.
That's my explanation and my opinion.