How do we know Christ's virgin birth is necessary for salvation?

The necessity of Christ's virgin birth is rooted in His identity as the only sinless human who could fulfill the law and represent us before God. According to Hebrews 4:15, He was in every respect made like us, yet without sin. If Christ had been born of a human father, He would inherit Adam's sinful nature, but being born of a virgin means He has no contaminated nature and can atone for our sins effectively. Romans 8:3 highlights that God sent His Son 'in the likeness of sinful flesh,' which is effectively realized through the virgin birth.