Despite their many pronouncements on children, neither the present Bible nor other early Christian tradition directly discuss in vitro fertilization or other modern aids to conception, for the simple reason that they were not invented until the late twentieth century. Viewing Christian literature before AD 250 as a whole, it appears that sex itself was discouraged or morally marginal while, as a category, procreation of children was welcomed.
The Old Testament regards the conception and bearing of children as a blessing from God. Although the New Testament and other Christian tradition are not as explicit, they contain a preferential option for the life of children. Jesus Himself said “Let the children come to me”(Matthew 19.14; Mark 10.14; Luke 18.16 // Diatessaron 25.44).and “whoever does not receive the kingdomof Godlike a child shall not enter it”(Mark 10.15 // Matthew 18.3; Diatessaron 25.10f, 25.45). A significant range of authors condemned abortion, which indicates that any opposition to sex does not extend to procreation. This is fortified by the prohibitions against murdering children after they are born and against “exposing” them, which was the Roman practice of abandoning unfit or otherwise unwanted newborns in wild places to die, or be picked up and raised as slaves by other people.
Whatever the pronouncements of some authors against sexual intercourse, they did not extend to conception and children as such. In fact, Aristides in AD 125 recorded that it was Christian custom to give thanks to God whenever a baby was born to members of their community(Aristides Apology 15). Moreover, 1 Timothy 3.4 and Titus 1.6 indicate that it was permissible for bishops/elders and deacons to have children; some Christians today even maintain that it is an indispensable qualification for the office.
In contrast, sexual intercourse was viewed negatively, or as the lesser of evils. All authors who commented on it regarded it as subject to many restrictions, some actually going so far as to say that it was forbidden even to the properly married (e.g. Clement of Alexandria Paedagogus Book 2 Chapter 10; Stromata Book 3; Acts of Thomas). A significant segment of the ancient literature prohibited sex without the intention of conception. Indeed, a major thesis of one twenty-first-century study is that Clement of Alexandria and Christian moralists for centuries after him asserted that sexual intercourse was permissible only when reproduction was the sole motive, and that Christians must avoid taking pleasure in it—Kathy L. Gaca The Making of Fornication: Eros, Ethics, and Political Reform in Greek Philosophy and Early Christianity (Berkeley: University of California Press, 2003). Nevertheless, Saint Paulcommanded that one spouse give conjugal rights to the other (1 Corinthians 7.3), and the otherwise negative Origen permitted sexual desire for the end of begetting a baby (Homilies on Genesis 2.6).
Thus there appears to be a division in moral status between (1) sexual intercourse, which was prohibited, discouraged, or at least hedged about with many restrictions, and (2) conception, which was usually regarded as desirable. This division severed the link between the two, and resulted in a contradiction that was insoluble prior to the development of in vitro fertilization. It would seem that the biblical and traditional opposition to or restrictions on sex were directed not so much against the emission of bodily fluids, but against the passion, strong feelings, impairment of reason, and the chance that an activity might distract a participant from God’s glory. In many writings, the ancients strongly discountenanced such emotions in non-coital situations as well. In vitro fertilization would satisfy even the most stringent of early authors, for they disapproved of sex without conception, while modern procedures make possible conception without sex.