There are those who say human life begins when we take our first breath. Does the fact that unborn children don’t breathe air mean they aren’t yet live human beings? Does the Bible teach this in Genesis 2:7 when it talks about the “breath of life” in the account of the creation of Adam, as some claim?
The first thing to note when responding to those who hold this view is that Genesis 2:7 isn’t about Adam’s breath. Here’s what it says:
Then the Lord God formed man of dust from the ground, and breathed into his nostrils the breath of life; and man became a living being.
Adam breathing isn’t what gave him life. The point is that God gave life to Adam by breathing life into him. This passage is about God giving life to His creation. There is nothing in here about Adam breathing—though, of course, we can assume Adam began to breathe after being given life since that’s the way adults normally function. (Note, here, that according to 2 Timothy 3:16, Scripture is also “breathed out by God.” God “breathing” something out is not about God’s literal breath but about the giving of something from God to us.)
Second, Adam is a unique situation. How God created the first human being is not related to how human beings are created today, so it doesn’t make sense to draw conclusions from how God gave life to the first man (by His “breath,” not Adam’s) that apply to every single human being who was subsequently born in the normal way. In fact, there is no mention of God ever “breathing the breath of life” into any other human being—not even Eve, though she was also directly created by God. Adam was unique, the first living human being. God gave him life in a special way to start everything off. After him, Eve was taken out of already-living Adam—made from his rib, not non-living dust. It makes sense that there would be no breathing of life into her because she was made from living material. After Eve, like begat like—complete human beings, whose essence is both body and soul, beget complete human beings. Children come from the joining of a living man and woman; so in the same way as Eve, there is no special breathing of life into them, either.
The third thing to note is that the unborn are “breathing”—that is, like human beings in other stages of development, they’re receiving the oxygen they need for their cells to function, though not through their mouths. Yes, Adam required breath to live, but again, Adam was a special case. He was created and given life as an adult man. Adam started breathing air at that time because that’s how adult men receive oxygen. It doesn’t follow from the fact that God gave life to Adam at a developmental stage where one breathes through one’s mouth that therefore no human being is alive until he also breathes through his mouth. The unborn begin life in a completely different way from Adam—they’re not created as adults from non-living material; they begin when an egg and sperm come together, and they receive oxygen the way every human being is designed to receive oxygen at that stage of life. Just because an unborn child is not an adult and doesn’t take in oxygen the way an adult does, that doesn’t mean he isn’t receiving the oxygen he needs to live; and it certainly doesn’t mean he isn’t a live human being.
But perhaps the person challenging you is not arguing that being able to breathe air is the all-important difference between the born and unborn that makes us human. He is more likely arguing, based on his reading of Genesis 2:7, that the moment we first breathe is the moment God gives each of us a soul (see here for an example of this). If, after some careful clarifying questions, you determine that this is the argument he’s making, go through an explanation of the Genesis passage with him, and then take him to Luke 1, where he will see that John the Baptist was “filled with the Holy Spirit while yet in his mother’s womb” (v. 15) and “leaped in [Elizabeth’s] womb for joy” (v. 44) when Mary, pregnant with Jesus, greeted Elizabeth. This is not a description of a soulless body.
When talking about newly-conceived human beings—and not the first (and only) adult man directly created from non-living matter by God—the Bible gives no indication that there is a time before birth when we are not whole human beings but merely bodies without souls. If one is going to speculate that God completes the essence of a human being by adding a soul at some point after conception, please keep in mind that all this can be is speculation. There is no good biblical reason to think it’s true; and, in fact, the Luke 1 passage seems to directly contradict it.