Back when Noah was chosen to build the ark, the fallen angels had mated with humans, they were mixing breeds of animals and making new breeds, and there was so much corruption that God chose to end it. Noah and his family were the only ones who had stayed 'pure'. There was no change in the pedigree so to say. this had to be done for God's plan to be fullfilled that Jesus would be born from a clean line.
today, there is so much corruption in our world...some times I think the rain that doesn't ever seem to stop is God crying. Homosexuals are leading churches, some churches are corrupt with sin, sex outside of marriage, murder, lust, pornography and the list goes on and on. Satan was given reign over us until God sees the time to come and take back what is His. That time is close.