Pilgrim
Thank you for your help on this issue. As you probably know all too often in debates on baptism both sides can be guilty of misrepresenting the other side and I believe that is shameful. That is why I like to understand both sides properly.

Why should we be afraid to study both sides?

I did a little more digging on RC Sproul and Ligonier Ministries view on the subject of “Presumptive Regeneration”.

One such article at Ligonier Ministries is called: Pray For Your Children's Salvation (ligonier.org)

Here is a quote:
Quote
According to God's promise (Gen. 17:7; Acts 2:39), the children of believing parents are included in the covenant of grace and must be received as members of the church by baptism. This promise is precious, and the privileges it confers on our children are great indeed. But they afford us no ground to presume that our children are regenerate and no reason to treat them as such before they come to saving faith and repentance.
We baptize infants based on many points, but not on account of "presumptive regeneration." The results of this view, which says that we must assume all covenant children are regenerate unless by flagrant sin they prove otherwise, can be quite tragic. Knowledge and morality are often substituted for salvation, without Spirit-worked regeneration, conviction of sin, repentance unto life, saving faith, and the necessary fruits that accompany it (John 3:5; 16:8-11; Luke 13:1-9; John 3:16; Gal. 5:22-23). Knowing God savingly and personally is then replaced with engagement in "kingdom activities" at home, in church, at school, and in the community at large.

I am not sure what the disagreement between Sproul and his mentor was. However, the quote above shows me that it probably was not on ‘Presumptive Regeneration’.

Tom