High Christian Birthrates and the Growth of Early Christianity

I’m in the middle of a book entitled: The Rise of Christianity: How the Obscure, Marginal, Jesus Movement Became the Dominant Religious Force in the Western World in a Few Centuries by Rodney Stark. The book does not attempt to attribute the rapid growth of Christianity to anything supernatural, but looks purely to natural explanations for why Christianity flourished. Interestingly, one reason the book gives for this is that Christians had much higher fertility rates than their pagan contemporaries.

Within the first five centuries A.D., abortion, infanticide, and the use of birth control were widely practiced in the pagan world. Greco-Roman literature reveals that abortions were common even though they were extremely dangerous. Women sought abortions to hide sexual activity, to avoid having children that could not be afforded, especially if a woman was poor, or if rich, to avoid sharing the estate with many heirs. Men, as heads of households, could also legally order a woman to have an abortion. There were many methods available to women for obtaining abortions, but most were damaging to reproductive organs and/or deadly. Thus, the practice of abortion not only reduced the number of births, but also either killed women before they had any children or led to infertility. Added to this, pagans in the Greco-Roman world practiced infanticide. The practice was advocated by law and by philosophers (e.g., Plato and Aristotle). If a child were born a female or with deformities, Roman legal code allowed these to be exposed as infants. Commonly, infanticide involved leaving newborns outdoors or throwing them into sewers. With the preference of male children over female, this largely reduced the capacity for population growth. As far as birth control, those in the pagan world took a variety of measures to avoid fertility. All these things contributed to the extremely low birthrates among pagans. There was for certain a shortage of women, but more specifically a shortage of woman with the capacity to bear children.

Christians, to the contrary, had high birthrates. For starters, Christians highly valued women. The average woman was afforded a much greater level of respect and privilege within Christianity than outside. Second, Christians emphasized that one of the primary purposes of sex was to bear children. Thus, having children was a marital duty. Third, Christians prohibited abortion and infanticide, considering both to be acts of murder. Being against abortion, Christian women were less likely to have damaged reproductive organs or die from the practice. Being against infanticide, more females, and thus more with a capacity to bear children, were born into Christian households. Fourth, Christians were far less concerned about preventing childbirth with birth control. All these things made for extremely high birthrates among Christians.

In conclusion, while pagan birthrates were low, Christian birthrates were high. This is one reason why Christianity grew so rapidly. Their attitudes toward sex, women, pregnancy, children, and abortion contributed to their birthrates being much higher than society around them.