How did Jesus escape original sin?

Does sin have a ‘genetic’ nature, since all mankind is “born” into sin? In which case, how did Jesus escape original sin since He was born into the same sin-cursed world?

Your question makes the right assumptions. There is no doubt that sin’s presence in humanity is more than coincidental. From Adam forward, there is none righteous — no, not one (Romans 3:10). All of humanity is under that sin’s curse, expressed principally as death. Jesus became human — not in facsimile only, but in reality. And yet somehow, Jesus, even in his full humanity, is not affected by Adam’s fall in the same way the rest of us are. Although He dies, He does not sin. How does Jesus escape the otherwise universal transmission of Adam’s original sin?

To address whether sin has a “genetic” nature requires asking what is transmitted from one generation to the next, and how. If condemnation alone were passed down, the genetic question would not even come up. However, all people begin their lives not only under condemnation, but already stained by sin — in whatever form, to whatever extent. Because every single person (past, present, and future) carries sin’s curse forward, it appears to be an essential rather than accidental characteristic of fallen humanity. It would be meaningless, for example, to explain away the severity of what is inherited by each subsequent generation as nothing more than an inclination. The only value to calling it an inclination, rather than the inescapable presence of sin itself, is that someone might be able to resist it. But none do, and none can. Sin’s presence is universal.

The next question, then, is how that sin is transmitted. One tradition, called Traducianism, contends that everything about a child is received from his parents — both body and soul; that is, the material and immaterial. In such a world, it is easy to see how sin would have a “genetic” component, in the words of your question. Just as a son could receive dark skin and brown eyes from his parents, he could also receive sin. But there is another view called Creationism, which claims that each soul is created by God when the material body is formed. In this view, the sin’s conveyance to the child is less directly analogous to biological genetics, requiring, for example, that God either impute or impose the sin of the ancestor into the progeny. Both views (Traducianism and Creationism) are biblically defensible. And importantly, regardless of whether there is an agreed-upon mechanism for bringing about sin’s transmission, the point is that every single person since Adam is infected with sin. To be redundantly clear: although there are many and divergent views about how sin is passed down to children, there is no dispute in any form of orthodox Christianity about whether it is passed down.

There is one sense in which Jesus does not escape sin at all — when He takes on Himself the full brunt of our sin

‘Complete’ humanity

So how does Jesus escape that sin? How can Jesus be fully human but not carry what appears to be an essential attribute of humanity, original sin? There are many speculations about how Jesus’ virgin birth or divine nature precludes the presence of original sin in Him. The explanations vary depending on which tradition undergirds them. Some are perfectly viable; others strain credulity. But the mechanism is not the point. The thing which sets Jesus apart is that He is the last Adam. He is as untainted by sin as Adam before the fall. And He does in His unfallen humanity what unfallen Adam failed to do. He overcomes the temptation. He lives without sin. So we end up with two things constantly being affirmed about Jesus: He is completely human, and He is completely God. The fact that He is completely human means He is just like every other human, a lesson emphasised in the epistle to the Hebrews: “He was in all things tempted like we are” (Hebrews 4:15). The fact that He is completely God means He is different from every other human, which is why the author of Hebrews concludes the previous phrase: “yet without sin”. Whatever the mechanism, it seems inevitable that Jesus’ sinless nature is inextricable from the “hypostatic union”, the union of divine and human nature in the one person of Jesus. The need for atonement to be through a sinless sacrifice is why there is an endless succession of messianic figures (Abel, Noah, Abraham, Joseph, Moses, David, Stephen, Paul; to name only a few of the most prominent), but only one Messiah: God Himself having descended to become human, precisely to overcome humanity’s bondage to sin.

The stumbling block for some is that if Jesus does not participate in humanity’s fallen nature, He does not seem to participate in humanity’s full nature. But that idea fails to recognise that God created humanity sinless, not fallen. Jesus is the completeness of humanity. Every man since Adam’s fall has been an inaccurate record of human nature. In Jesus’ perfection, we see what Adam would have been without sin (the term “apotheosis” is appropriate here), and that to which the redeemed will be restored in the resurrection.

A last word is merited, though distinct from the intent of your question. There is one sense in which Jesus does not escape sin at all. Indeed, He takes on Himself the full brunt of our sin. Paul says in Galatians 3:13 that Christ became a curse, and in 2 Corinthians 5:21 that He became sin — in both cases for us. In His suffering and death, He does anything but escape our original sin. He takes it on Himself, and so removes its power from us. In this redemptive act, we find salvation by grace alone, through faith alone, in Christ alone.