We have contended on this blog that the Pedobaptists maintain their church membership primarily by infant baptism, adding the infants to the church as bonafide "born again" members. This is based on their supposed "covenant" teaching, that infants born to Christian parents are allegedly "covenant children" who inherit the promise of regeneration, supposedly received in early infancy, and signified and sealed by infant baptism.(all errors and emphasis in original) (link to Ross' inaccurate blog article)
a) In general, Reformed Paedobaptists (PB) distinguish between covenant members and communicant members. Communicant members normally only include those who have demonstrated regeneration by a credible profession of faith.
b) The idea that Reformed PBs "maintain their church membership primarily by infant baptism" is inane. Such a stratagem would work for precisely one generation. In fact, it may sadly be the case that some PB's do not properly remove from their rolls covenant breakers. On the other hand, the primary way in which the membership of PB churches is maintained in Christian lands is by evangelization of covenant members. That is to say, PB churches tend to gain the same communicant members that non-PB churches tend to gain: children raised in the church.
c) While some small minority of Reformed PBs may have taught an idea of baptismal regeneration, it would be improper to characterize such as the standard teaching. Instead, the bigger issue is the question of whether we should assume that the children of believers are regenerate or unregenerate before we see evidence either way. Some say we should assume that they are regenerate, others say contrariwise.