If Jesus were not fully human and fully God, and if He were not virgin born, then we would not be able to go to heaven. Here’s why.
We are separated from God due to sin, because God is holy and we are sinful. Because we have sinned, God, being just, must be a just judge and condemn sinners. However, because God is also loving, he has provided a way for us to be saved: Jesus paid our price for us……Jesus died for us, so that we don’t have to.
If Jesus were not fully human, He could not have died for humans; He could not have paid the penalty for humans. If He were not fully God, He could not have been a mediary, for a mediary must have an interest in both sides. Further, without being fully God, Jesus could not have been sinless.
The virgin birth is also significant. The bible teaches that humans inherit sin from our parents, the sin nature that originated with Adam and continues all the way to us. If Jesus were not virgin born, He would not be God, but merely human, and would have inherited a sin nature.
So both the virgin birth and Jesus being born as a human baby were absolutely essential for us to go to heaven. Those who deny these central doctrines of the faith are outside of Christianity.