Families that are broken are often referred to as "dysfunctional". By contrast, we read in the Gospels that our Lord grew up in a highly functional family.
Matthew 1:19 tells us of the righteous character of Joseph. His treatment of Mary after learning she was pregnant—and before the angel explained to him what was happening in her body—was remarkably gracious. We might imagine Joseph to have been a very gentle and patient husband, father and neighbour.
What is especially interesting is how very much attention is given to Mary's response to the events surrounding her Son's birth and childhood.
Perhaps it is assumed that Joseph carefully thought over the remarkable events in their Son's life, but it is clearly stated that Mary "pondered" them.
Dr. Luke—who wrote the Gospel carrying his name—has special interest in widows, public sinners, children, people in need, and women. So we expect him to tell us most about Mary's point of view, while Matthew gives us Joseph's account of the proceedings.
Clearly, Joseph and Mary were not perfect parents, however, we also know nothing negative about them.
The teaching concerning Jesus is that He is sinless (John 8:46; 1 Peter 1:19 and so on). Our Lord is the perfect second Adam (Romans 5), and only as such could He atone for the sins of the world. As Jesus spent about 30 years under the watchful eyes of Mary and Joseph (we don't know when Joseph died), they never witnessed a single incident when He sinned, demonstrating the sinful nature of others.
We believe that Jesus, as man, is sinless for reasons other than the various statements in Scripture.
The fact that our Lord did not have a human father is also a reason why we believe His human nature is sinless. Romans 5 tells us that we all inherit our sinful nature from the first Adam. Had Joseph been our Lord's biological father, then His human nature would have been tainted with sin. The Virgin birth is thus a very necessary part of the story of redemption.
As you sing the carols of Christmas this season, rejoice in the perfect Sacrifice made for your sin. Your Saviour is the only One Who could atone for your sins because He alone did not have to atone first for His own sins.
Hebrews 7:26-27 assures us that the sinless One made the perfect—and only—sacrifice for sin. None other was good enough, no one else could do what He did.
Hallelujah for the perfect Son Who made the one perfect sacrifice for all time and eternity. Celebrate Christmas enthusiastically because the family that was "almost" perfect did provide the perfect One and He has made the perfect solution for the sins of His people.