'____ Gene'

I don't know if it's just me but I've now been noticing within our society people are confusing nature and culture, many believe 'I was born gay' or 'I was born poor'. Many people think because of their environment or their situation it becomes apart of them which is true 'culture' but people are trying to erase the line between biology and culture. So it looks like there is some type of gene that makes you the way you are. For example, Lady Gaga's song 'Born This Way' you can say it's just a song, there is no harm to it but there is. It confuses people to believe that there is a 'gay gene' out there but there is no such thing.
We talked about this in class, there is no 'smart gene' even if both of your parents are rocket scientist doesn't mean you will be one too. There is a possibility you can do something related to science or not at all, it depends on the environment you've grown up in.

Skyline

So I watched the movie Skyline after my Dance Company performance last night and there was a scene where one of the main characters died not because they were weak, it was just by chance their body couldn't handle the pain so they ended up dying. 

According to Darwin only the strong will survive because they are the fittest. Now, my question is what happens when someone dies unexpectedly? Is it because they weren't fit enough so they were rooted out or was it just chance they happen to be crossing the street when a man drunk off of road rage forget to stop at a  red light and kills them. They didn't die exactly because there weren't the fittest but it was just by chance they did. Also even if the strong survive we all have to die at some point because we can't live forever so is it apart of us we are all destined to die one day.