It was scientific for the positive and negative mutually for the cooperation to fulfill human life purpose and joint energy together with both sex for extending life perpetually. It was Tibet highland harsh environment so that it's population was not enough for me to discovered this theory however this culture was experienced in artful so it need more improvement for the perfect. Nore: sex was beginning of family, tribes and nation that need to joint together for good. Too much population for the encomy burden that may a good reason against it?
Every culture has its own unique vitality. No matter where it is produced, it will have its inevitability. Whether it is art or religion, each independent individual has its own meaning of pursuing life.