Today's daf is sponsored by Judy Shapiro in loving memory of her brother, David Tychman, on his 10th yahrzeit. “David was a lover of Israel, a lifelong collector of Israeli stamps, and he would have been so saddened by the events of the past 2 1/2 weeks. Am Yisrael Chai!” There is a debate about whether a convert can marry a mamzer. Rabbi Zeira taught in Mechoza, a city with many converts, that a convert can marry a mamzer and got pelted with etrogim as the converts were insulted by it. Rava then came up with a more sensitive way to teach the halakha. According to Rav, a shetuki (unknown father) and asufi (unknown parents - abandoned child) can marry a Jew by Torah law as it is unclear whether they have flawed lineage or not (safek), but the rabbis wanted to institute a higher standard for yochasin, lineage matters.  An abandoned child is not always considered an asufi (flawed lineage) as it depends on where (and why)  the baby/child was abandoned. If it seems clear the parents abandoned the child as they couldn't afford to feed the child, then the child is not considered to have a flawed lineage. What are potential signs that the child was abandoned in this way? If an abandoned child was picked up by people claiming to the the parents, they are trusted but not if the child was already picked up by someone else. This is similar to two other situations where one is believed only if they respond immediately - a midwife who testifies regarding twins about which child came out first (only while she is still in the room or hasn't turned around), and a woman who was with other women in a bed that was stained with blood and she claims it was from her and proves it through an internal check that was performed immediately after the stain was found.