Both .
You can say a mother not eating her children is evolution or survival , but it is also translated as a moral issue . Since not eating your children is not particularly subjective or learned , it would be false to claim that ethics are just learned or subjective . The fact that some mothers have eaten their children is the exception that proves the rule . This is one of the first things one would learn on introduction to ethics at university :)
Teen bonobos like to handle other infants and show increased oxytocin . Despite horrors , genocide , abuse or even simple impatience and disregard , humans are capable of extremely high levels of complex and complete empathy .
To answer question directly: people are indeed born with a strong sense of morality/humanity , and then they learn some more .
Hume claimed that moral evaluations depend on our sympathy and empathy , which are innate . Our modern theories of justice , "Justice As Fairness" , suggests phrasing ethical rules by a dynamic social contract (not the Rousseau type) . Humans are born with a strong sense of bonds . This is the essence of ethics and essential to its existence . So the innate is actually a significant part and cause of ethics and morals . Communication and community are highly-developed core attributes of the specie .
The other things are really 'just' fine-tuning (which are marvelous of course) . A human lives entirely in his or hers cognitive-linguistic narrative , so he or she will naturally and rightly focus entirely on that 'fine-tuning' discussion , rather than not eating their children . That discussion is vast , nuanced , and often dynamic.
Dogs do not bark categorical imperatives .