Mishneh Torah, Forbidden Intercourse 15-17

Sugya Map: The Definition of Mamzerut

• Core Issue: Does mamzerut require a specific prohibited act (e.g., adultery) or merely the outcome of any forbidden sexual union?
• Nafka Mina: The status of offspring born from rape or ignorance (shogeg).
• Primary Sources: Mishneh Torah, Forbidden Intercourse 15:1; Chagigah 10a; Yevamot 49a.

Text Snapshot

"When, however, a man enters into any other forbidden sexual relationships, whether through rape, or willingly, whether conscious of the prohibition or not, the offspring produced is a mamzer." (MT, Forbidden Intercourse 15:1)

Nuance: The Rambam uses "הבא על שאר העריות" (the one who comes upon the rest of the forbidden relationships). The Leshon implies a categorical classification: mamzerut is an objective status of the offspring, independent of the subjective ratzon (will) of the parents.

Readings

• Kessef Mishneh (ad loc): Notes that while Rambam identifies Chagigah 10a as the source, he famously omits the specific Talmudic citation, treating the severity of mamzerut as a fundamental halachic axiom regarding the integrity of the Jewish lineage.
• Pnei Yehoshua (Chagigah 10a): Argues that mamzerut is not merely a punishment for the parents' sin but an ontological "stain" on the offspring. Thus, even if the sexual act lacked mens rea (e.g., ones), the status of the child is fixed by the prohibition of the underlying union.

Friction

• Kushya: If mamzerut is a result of a prohibited union, why is the niddah child merely pagum (blemished) rather than a mamzer?
• Terutz: The niddah prohibition is a temporary prohibition (issur lav), whereas the mamzer-producing prohibitions are fundamental violations of the structure of the Jewish family unit (issurei ervah). The mamzer status is reserved for the violation of the congregational boundary, not just the sanctity of the act.

Intertext

• Deuteronomy 23:3: "A mamzer shall not enter the congregation of the Lord." The Sifra (Emor 2:4) bridges this to the Rambam's insistence that the status is "everlasting" (le-olam).

Psak/Practice

The Rambam’s meta-heuristic is that lineage (yichus) is a public, objective status. Even if a father claims his son is illegitimate (mamzer), he cannot disqualify him if the son already has his own children (MT, Forbidden Intercourse 15:15). The law prioritizes the stability of the public record over the private truth of the biological father.

Takeaway

Mamzerut is not about the guilt of the parents, but the integrity of the community; the law protects the community's lineage even at the expense of individual subjective intent.