How old is too young for a female to get pregnant? 21? 18? 16? 14? How about 1? Perhaps the thought of a pregnant 1 year old is disgusting to you, and you'd be absolutely right. If I was talking about a human. However, a domestic cat can begin mating as early as 5 months old. Thus, a year is hardly a stretch. Evidently, the ideal age of consent is different between species.
How old was Mary when she gave birth to Jesus? The truth is, we have no idea. All we know is she was young enough to have been a virgin, and old enough to be engaged. It has been suggested that she may have been as young as 14. Without any hint of confirmation, some atheists have jumped on this to criticise Christianity. How could God not only allow, but call on a 14 year old to get pregnant? How evil! Right?
First, let's get this out of the way: We have absolutely no idea how old Mary was. Because of Jewish customs at the time, she might have been 14. However, she could have been much older. For sake of argument, let's just accept the 14 year old narrative. After all, this would be in line with the custom of the time.
Given that it was customary for younger females to bear children, it would make sense that the most Evolutionarily successful females would be the ones that were most capable of doing so. And indeed, religion as a whole does contribute to reproductive success. Women in the West tend to wait much longer to have children, and when they do, they only have one or two. By contrast, the Islamic world doesn't present many opportunities for women to do much more than produce children, and so they do so, which allows Islam to be the fastest growing religion in the world in spite of low conversion and high apostasy rates.
By criticising the possible age of Mary at the time she conceived Jesus, Evolutionists are ultimately denouncing their own religion. If Evolution is true, a woman getting pregnant at 14 should be no stranger than a cat getting pregnant at 1. Not only that, but the age of reproduction should not be fixed. Keeping in mind that some Evolutionists use the fact medieval (500 - 1,500 years ago) men were shorter than we are as "proof" of Evolution, it should not be unfathomable that 2,000 years is long enough for what was then a perfectly normal reproductive age to become totally unacceptable in our time. It should also vary between cultures. We should be able to say that 14 is still acceptable in cultures where it persists because that culture has simply evolved differently. Thus, attacking Mary's alleged age when Jesus was conceived is effectively saying Evolution, even within species, cannot happen, or at least not in such a short time as a large portion of their arguments require it to have happened.
Evolutionists are therefore forced to make a choice. They can claim 14 is, and always has been, too young for human childbearing. This opens up the possibility to attack Christianity, if they can A. prove Mary was absolutely 14 and no older when Jesus was conceived and B. prove that a moral source exists that would dictate what God can and can't do that He violated (which would be circular reasoning). However, it does rather fly in the face of Evolution, since if Evolution is true, there could have been a time in human history when 14 was an acceptable reproductive age, and given that this was basically the norm, 14 year olds should merely have improved their reproductive abilities, meaning even today 14 should be an acceptable reproductive age.
Alternatively, they can cling to their Evolutionary narrative. At this point, they lose the ability to criticise any custom or practice as "immoral". The best they can say is "this benefits survival and/or reproduction" or "this hinders survival and/or reproduction". Even then they have to define who for. Humans have driven several animals to extinction, which may have been good (e.g. large predators) or neutral (e.g. replaceable prey) for our survival. Morality in general disappears at this point, yet a large portion of the atheist case is based on emotional appeals to morality.
Of course, we all know why this is. Human beings, by nature, do not tend to agree with God's morality. We are rebels. Treasonous sinners seeking the throne for ourselves. We don't want to obey, and so like petty children, the mere possibility that God might order us to do something we don't want to, or not to do something we do want to, or basically any aspect of God's religion that we don't like, is used as "evidence" that God Himself is evil. In reality, it is evidence that we are evil.
And that is why however old Mary was, God chose to send Jesus through her. Our sin merits only one penalty: Eternal wrath. God must punish evil, but God also loves us, though we ourselves are evil. Thus, only one alternative was on the table: The death and resurrection of the Lord Jesus Christ. Faith in Christ grants us a clean slate. Will you take that offer?