Well of course our entire moral system is based on Christianity, just the same way as the moral of Saudi Arabia are based on Islam.
Reigions,and the morals dictated within them, were and are the chief methods by which dissent is suppressed among the uneducated masses.
It's almost a cliche to note that, throughout history, the working and middle classes have been cajoled, lectured, legally required and physically bullied into monogamy, producing children, self-denial and frugality. Meanwhile the aristocracy and/or plutocracy have carried on with being promiscuous, using birth control, being self-indulgent and extravagant.
But situations changed. Developments in agriculture and industry basedd on agriculture rendered slavery inefficient. Capitalism proved that paying a man starvation wages actually madehim a harder worker than a slave, whose owner was obliged to feed, clothe and house him regardless. This was why slavery was largely abolished in the West.
Advancing technology in industry spelled the end for the iliterate, innumerate, ignorant worker. But the educated worker demands that either the elite are held to the same moral standards he is, or that he is no longer obliged to adhere to standard spromulgated by or on behalf of the elite.
Advances in medicine, professional armies, improved diet and safer working conditions decreased boyj infant and adult mortality and contributed to a population explosion. Whihc is why the moral imperatives for family life -marriage and chlldren - have faded in importance, why birth control (once forbidden) is now considered proper behaviour. Itis also why debates on the separate but linked issues of abortion and euthanasia have intensified. Where once an unending supply of labour and cannon fodder was necessary, now there are too many of us and too many of us are getting too old to be useful. So now we need to find 'moral' ways of reducing population.
Morals and moral codes were never about good and evil, or right and wrong. They were and are about power and control.