MYTH: Christians cut their baby boys
Christians have, with very few exceptions, never practiced circumcision. From the Apostles Peter (Acts 15:5-10) and Paul* (in several places, including Galatians 6:12-15 and 1 Corinthians 7:18-20) and the Church Fathers, to Medieval Christians through the Reformation and beyond, God's children have never viewed circumcision as a Christian practice. Indeed, Christians have believed that Christ's finished work has abolished the practice and even made it reprehensible, just as animal sacrifices are now reprehensible. To circumcise without reason violates the biblical view of the human body.
Both before and after the Protestant Reformation, the Catholic Church has repeatedly forbidden Christians from being circumcised (or otherwise mutilated) without unavoidable medical reason. Protestants have never circumcised until the procedure arose in English-speaking countries in the late 1800s (see How MGM really started in the US). Nevertheless, secular thought introduced the practice in the modern United States, and American Christians absorbed it.
Christians in other lands are often shocked to hear that some American Christians routinely circumcise their boys. They view the practice as a lack of respect for God's wise creation and a clear violation of basic medical ethics.
MYTH: God commanded the modern form of circumcision.
The Old Testament’s milah circumcision is by all accounts not the same procedure that is practiced in the USA today. The modern procedure removes many times more tissue and multiple functions. Among Jewish scholars and documentary evidence, including from the Old Testament itself, there is no doubt that the ancient Jewish procedure was much less drastic. See a summary here, then check out more from The Oxford Dictionary of the Jewish Religion and over 50 citations of historical evidence. As a recent Jewish newspaper article noted, "the Biblical command for circumcision had its scope extended by the rabbis," probably in about 130 AD, in order to prevent its reversal.
Before this addition, circumcision did not lay bare the glans (tip). Only the foreskin proper was removed (click here for a drawing showing the difference). This left the foreskin's God-designed functions intact.
God has never authorized the modern, severely damaging amputation for any people group at any time.