An unbeliever starts to become disaffected by some of their native cultural norms and an egg moves away from the ovary to travel down the fallopian tube. A sperm enters the egg and something from God's word is received by the unbeliever. The fertilised egg inplants in the uterine wall and starts to receive nutrition from the womb. The unbeliever attaches to some member/s of the church and starts to receive nutrition from the church. The baby grows until it feel cramped and under pressure in the woman and wants to be released, and the unbeliever grows in understanding until they become uncomfortable and constricted by the world and wants leave the world. The child when fully developed secretes a small amount of protein that causes the woman to expel the child, and when the unbeliever has sufficient understanding of the gospel to start living as a Christian independently of the world they express a mustard seed of faith in Christ, which causes the world to react and expel them. This expulsion is often, but not always, traumatic for the mother and the child or both, but is necessary for the child to survive. and thrive Leaving one's cultural traditions to embrace the Christian Way is also often traumatic for the convert and their community, but is necessary for the newly-believing convert to survive and thrive.
Such a natural process God has designed for His creation. Too bad some never make it.
It would be fun to see how this could be more and more refined, and more parallels conceived (no pun intended).