Okay, I've never heard of anybody literally punting a baby (and I hope I never do!) But I've seen countless Christians do a spiritual equivalent of this with those they've led to Jesus. And, to be honest, I've been guilty of it myself from time to time.
When someone puts their faith in Jesus they are spiritual babies who've been "born again" into the family of God through faith in Jesus Christ (John 3:3-16.) And this is when we need to do our best to help these newborns grow spiritually by getting them connected to a healthy, vibrant church. Here (at church), spiritually mature Christians can get these new believers the truth of God's Word to help them grow, "Like newborn babies, crave pure spiritual milk, so that by it you may grow up in your salvation, now that you have tasted that the Lord is good" 1 Peter 2:2-3.
The church is the spiritual incubator for newborns to receive the spiritual food, nurturing and warmth they need to grow into healthy followers of Jesus. The following passage reminds us of the church's central role to helping spiritual babies grow into mature believers:
"So Christ himself gave the apostles, the prophets, the evangelists, the pastors and teachers, to equip his people for works of service, so that the body of Christ may be built up until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ. Then we will no longer be infants, tossed back and forth by the waves, and blown here and there by every wind of teaching and by the cunning and craftiness of people in their deceitful scheming. Instead, speaking the truth in love, we will grow to become in every respect the mature body of him who is the head, that is, Christ." Ephesians 4:11-15
The body of Christ is essential to enable the growth of spiritual babies into all God wants them to become. There is no plan B.
So, when you lead someone to Jesus make sure you do your best to then lead that newborn to a church where they can grow spiritually. If we don't then we are, spiritually speaking, punting the baby.