Luke's Gospel begins with a visitation of the Holy Spirit that results in conception; the book of Acts begins similarly, also with a visitation of the Holy Spirit that results in conception. In the Gospel it is Jesus, the Savior, who is conceived. In Acts it is the church, the company of the saved, that is conceived. The two Holy Spirit conceptions are meant to be understood as parallel beginnings to parallel narratives: both Jesus Christ and the community of Jesus Christ similarly conceived by the Holy Spirit...
But the births themselves (and this is important to observe) are completely natural. The Holy Spirit, however miraculous in the conception of life itself, doesn't seem to shortcut or skip anything that is human. There is nothing in a Holy Spirit-conceived life that exempts that life from the common lot of humanity. It didn't skip anything in Jesus, and it doesn't skip anything in us...
We are not to lose sight of the fundamental Jesus story line: what the community does and says and prays is continuous with what Jesus does and says and prays. This is the same Jesus story that we read in the Gospel but without Jesus being visibly and audibly present. The Holy Spirit is God's way of being present and active among us in the same way he was in Jesus.1

Eugene Peterson, Christ Plays in Ten Thousand Places, pp 268-270.