Niddah 34: Blood, Ziva, Jews, Non-Jews and Imparting Ritual Impurity

The Mishna on today's daf compares the blood of a menstruating gentile woman/gentile zava and the blood discharged by a female Jewish leper during the days of purity after childbirth.  Beit Shammai rule unusually leniently, deeming them ritually pure, and Beit Hillel argue that the blood of a gentile woman is the same as that of her saliva and her urine, which impart impurity only when moist.  They argue that even the blood discharged by a Jewish leper during those days imparts ritual impurity only when moist.  This refers to the seven days for a boy or fourteen days for a girl after child birth but before immersion.  

The rabbis discuss whether or not the transmission of impurity applies to both women and men.  And a gentile woman's saliva and urine might not impart impurity at all.  The Sages decide that the blood of a gentile woman is less common and it does impart ritual impurity.  

Moving along, the rabbis discuss the ziva, non-seminal discharge, of a Gentile man.  They also discuss the emission of the semen of a Gentile man by a Jewish woman.  His semen is considered to be ritually pure, and thus she is ritually pure even less than three twelve-hour periods after their act of intercourse.  Small amounts of urine are thought to escape with the emission of semen.  In the case of a Gentile woman who emits the semen of a Jew, the semen is impure because it came from a Jew.  The Gentile's semen is considered to be pure according to Torah law and impure according to rabbinic law.

Our daf continues to discuss the specifics of a zavim and lepers and their semen both inside and out of women's wombs.  

Today's daf mentions sexual relations between Jews and non-Jews casually and without commentary.  These relationships may be theoretical, but likely they were happening in the times of the Talmud as they happen in our times.