This is asked more often than it is written about, usually by people who are not Orthodox, have not been celibate, and are trying to work out whether any of it matters for the relationship they are actually in.
So: the traditional position, the reasons given for it, what the research does and does not show, and one very widely repeated claim that is false. JLov is a coaching practice and not a religious authority — nothing here is a ruling, and the halachic question belongs with your rabbi.
The traditional position
Traditional Jewish law prohibits sex outside marriage. There is more than one strand to the prohibition — the laws of niddah and ritual immersion, which apply to intimacy and have no mechanism outside marriage, and separate norms around seclusion and modesty.
Observance of this varies enormously. It is close to universal in Orthodox communities and close to absent in much of the rest of the Jewish world. Reform and Reconstructionist Judaism generally address sexual ethics through frameworks of consent, honesty, responsibility and mutual respect rather than through a marital-status rule.
The reasons traditionally given
Scarcity and value. The argument most often heard is that what is rare is treated as valuable, and what is ordinary is treated as ordinary. Intimacy reserved for one relationship carries a weight it cannot carry when it is a normal feature of dating. This is a claim about meaning rather than a claim about biology, and it is worth engaging with on those terms — it either matches your experience of what makes things significant, or it does not.
Clarity about why you are together. A relationship that is not sexual early has fewer ways to feel like it is working while the substance is unresolved. Whether that is a feature or a constraint depends on your view, but the mechanism is real: physical intimacy is a powerful source of the feeling of closeness, and that feeling can outrun the evidence.
Marriage as the container. Judaism does not treat sex as regrettable. Within marriage it is an obligation on the husband toward his wife — onah — and her pleasure is the point of it, which is unusual among ancient legal systems. The tradition’s position is about location, not about disapproval.
What the research actually shows
There is a real finding here, and it is routinely overstated in both directions.
Several studies using US national data have found an association between a larger number of premarital sexual partners and a higher likelihood of divorce:
- Teachman (2003), analysing the National Survey of Family Growth, found that women whose premarital sex and cohabitation were limited to their eventual husband showed no elevated risk of marital dissolution. Women with more than one intimate premarital relationship did.1
- Smith and Wolfinger (2024) is the most important of these and the most recent. Using the National Longitudinal Study of Adolescent to Adult Health, they found the association held up when adolescent beliefs, values, religious background and personal characteristics were controlled for. Those with nine or more premarital partners had the highest divorce risk, followed by those with one to eight. Their conclusion is worth quoting in substance: the selection mechanisms previously assumed to explain the link were not supported, and future work should look for either different selection effects or a causal one.2
- Busby, Carroll and Willoughby (2010), with 2,035 married people, found sexual restraint associated with better sexual quality, communication, satisfaction and perceived stability — controlling for education, number of partners, religiosity and relationship length. The lead author was blunt that they found no support at all for the idea that early sex helps establish compatibility.3
- Rosenfeld and Roesler (2019) found premarital cohabitation associated with higher divorce risk in the later years of a marriage.4 This one is genuinely contested: Manning, Smock and Kuperberg published a formal comment disputing the analysis, and Rosenfeld replied.5 Treat it as unsettled.
The caveats, which are not optional. These are observational studies, not experiments. Nobody has randomly assigned anyone a number of partners. The usual objection — that religious or conscientious people both have fewer partners and divorce less, so the partners are incidental — is the obvious one, and it is exactly the objection Smith and Wolfinger tested and did not find support for. That does not establish cause. It does mean “it is just religiosity” is no longer a sufficient answer.
Much of this research is on women, because that is who the older surveys sampled. The 2024 study covers both, and findings on sex differences are not consistent across the literature.
So the defensible statement is: more premarital partners is reliably associated with higher divorce risk in US data; the association survives the controls researchers expected would explain it away; and nobody has yet shown what the mechanism is. That is stronger than the usual hedge and weaker than proof.
What might actually be happening
Nobody knows. But two mechanisms have decent evidence behind them, and both are about emotional investment rather than about biology.
Sliding rather than deciding. Stanley, Rhoades and Markman described how couples accumulate constraints — a shared bed, a shared lease, a shared social life — without ever making a decision, and how those constraints then make it hard to leave a relationship you would otherwise end.6 Sex is the first of those constraints and usually the earliest. It does not commit you, but it makes leaving cost more, and it is entirely possible to end up married to someone you never actually chose.
Attachment running ahead of assessment. Physical intimacy produces a powerful sense of closeness quickly. That feeling is real, and it is not evidence about the person. The practical problem is that it arrives before you know much, and it is comfortable enough that the harder conversations can be postponed indefinitely — because the relationship already feels close.
People sometimes reach for oxytocin to explain this. Be careful with that: the pair-bonding chemistry is well established in some animals and much less cleanly mapped in humans, and the popular version — that sex chemically bonds you to someone against your judgement — overstates what is known. The behavioural account above does not need the neuroscience to work.
There is a version of this that matters more than any of the research. A relationship where intimacy arrives early can feel like it is progressing while nothing is actually being built — and people stay in those for years, waiting to feel certain, because the feeling of closeness keeps refreshing. That is the connection to the thing this practice says constantly: love is a choice, not a feeling. If the relationship is running on how it feels, the feeling will carry it a long way past the point where you should have asked whether you want the same life.
One claim you may have heard that is not true
It circulates in Jewish outreach settings and elsewhere: that a previous sexual partner leaves a genetic or epigenetic imprint on a woman, so that later children carry something of him.
This is false for humans, and it is worth knowing where it came from. A 2014 study at UNSW found a non-genetic paternal effect in a fly — Telostylinus angusticollis, a neriid — where the size of offspring was influenced by the female’s previous mate rather than by the male who actually sired them.7 That is a real and interesting result in that species.
It was then reported as though it applied to people. The researchers themselves said plainly that it does not.8 There is no evidence of telegony in humans, and the idea was examined and discarded in the mammalian literature more than a century ago.
It is sometimes confused with fetal-maternal microchimerism, which is real: cells from a fetus can persist in a mother’s body for decades. That arises from pregnancy, not from intercourse, and says nothing about previous partners.
The claim is repeated because it makes an argument feel scientific. It is not, and a tradition with real arguments available to it does not need a false one — particularly one aimed almost entirely at women.
What to do with all this
If you are observant, the question is settled and not by an article.
If you are not, the useful question is not whether you have a past — you almost certainly do, and so does the person you are dating. It is whether the two of you are using intimacy to avoid a conversation. Sex can make an unresolved relationship feel resolved for a long time, and that is the actual risk, whatever your view of the tradition.
The practical test is unglamorous: are you clear about what this relationship is, where it is going, and on what timeline — and would you still be clear if you stopped sleeping together tomorrow. How long you should date before talking about marriage is the same question from another angle.
References
- Teachman, J. D. (2003). Premarital sex, premarital cohabitation, and the risk of subsequent marital dissolution among women. Journal of Marriage and Family, 65(2), 444–455. doi:10.1111/j.1741-3737.2003.00444.x
- Smith, J., & Wolfinger, N. H. (2024). Re-examining the link between premarital sex and divorce. Journal of Family Issues, 45(3), 674–696. doi:10.1177/0192513X231155673
- Busby, D. M., Carroll, J. S., & Willoughby, B. J. (2010). Compatibility or restraint? The effects of sexual timing on marriage relationships. Journal of Family Psychology, 24(6), 766–774. doi:10.1037/a0021690
- Rosenfeld, M. J., & Roesler, K. (2019). Cohabitation experience and cohabitation’s association with marital dissolution. Journal of Marriage and Family, 81(1), 42–58. doi:10.1111/jomf.12530
- Manning, W. D., Smock, P. J., & Kuperberg, A. (2021). Cohabitation and marital dissolution: a comment on Rosenfeld and Roesler (2019). Journal of Marriage and Family, 83(1), 260–267. doi:10.1111/jomf.12724 — with Rosenfeld’s reply.
- Stanley, S. M., Rhoades, G. K., & Markman, H. J. (2006). Sliding versus deciding: inertia and the premarital cohabitation effect. Family Relations, 55(4), 499–509. doi:10.1111/j.1741-3729.2006.00418.x
- Crean, A. J., Kopps, A. M., & Bonduriansky, R. (2014). Revisiting telegony: offspring inherit an acquired characteristic of their mother’s previous mate. Ecology Letters, 17(12), 1545–1552. doi:10.1111/ele.12373
- University of New South Wales (2014). Another twist in the evolving story of heredity — the researchers’ own account, stating the finding is in flies and that there is no evidence of telegony in humans.
Every reference above has been checked against the published record. Where a finding is disputed in the literature, the dispute is cited too.