1. The Gemara explains why the Kohen who looks over the edge of the pit into which a stillborn was cast remains Tahor.
2. There is a dispute about a woman who did not examine herself at the time she was due to menstruate.
3. There is a dispute about how many times a woman who handles Taharos must examine herself throughout the night.
4. There is a dispute about whether it is inappropriate for a righteous person to have relations multiple times in one night.
5. While most features of a person are determined by Hashem, only the person himself can determine whether he will be righteous.
A BIT MORE
1. The Beraisa teaches that a Kohen who looks over the edge of a pit in order to see whether a stillborn -- that was cast into it -- is male or female is considered Tahor. One explanation for why he is Tahor is that an animal is assumed to have taken the stillborn out of the pit.
2. Rav: If she examined herself later and found that she was Tamei, she is Tamei. If she found herself to be Tahor, she is Tahor. Shmuel: Even if she found herself to be Tahor, she is considered Tamei, because a menstrual period is always presumed to come on time.
3. Beis Shamai: She must examine herself once before and once after every time she has relations. Beis Hillel: She must examine herself once before the first time she has relations and once after the last time she has relations.