Christ was born sinless,
but apparently not perfect. He was perfected in his death.
For it was fitting for him for whom are all things and through whom are all things in bringing many sons to glory to perfect the originator of their salvation through sufferings. Hebrews 2:10
This isn't too popular a concept because of what our Christian tradition says (i.e. that Christ was born perfect), but scripture can't be broken. Yes, Christ was perfected by what all he suffered through.
---
Such a concept (of Christ being perfected) seems contradictory because of (what I feel) is an equally incorrect tradition Christians subscribe to; that of "inheriting Original Sin from Adam". I don't think "Christ being perfected" is contradictory at all.
I don't know how the majority of CC members feel about this issues, but from Christians I've talked to in person, many believe that all people are "born sinful" because of Adam's sin, when instead scripture says we are "born in corruptible flesh" because of Adam's sin...and that corruptible flesh compels us to sin. But the former is what many Christians believe. However, "Original Sin" is another doctrine passed down to the rest of the Church from Roman Catholicism.
Sin is not a "condition" but an action (i.e. the act of disobeying God), while our corruptible flesh is the "condition" we've inherited from Adam. By this reasoning, I believe
all are born sinless (i.e. we haven't yet been disobedient), but all - except one - have sinned (i.e. have disobeyed God), and that exception is Christ. The rest of us have succumbed to the desires of our corruptible flesh at some point in our lives and have sinned (i.e. have disobeyed God) as a result.
So
ALL have the ability to disobey God (i.e. sin) including Christ (else Christ's temptation would've been pointless like HeRose says),
and ALL are compelled to sin (because this flesh is at war with God),
but only Christ resisted this flesh and showed he loved God enough to remain obedient to him (i.e. not sin) all of his life.
Only when Christ died could it finally be said that he "lived a perfect life...all of his life"; only when Christ died could it finally be said that "he was/is perfect, in obedience".