We ask the following database query: When our brother-sister genealogies used? The reader is encouraged to perform the query using a standard Biblical Konnkordance or search engine. This database query yields the list below. The list justifies the inference that Most genealogies are parental. Brother-sister sibling genealogies indicate a special relationship such as protection or assistance in marriage. The list below presents the results of the database query and provides examples.

Verse	Brother Sister	Suggested Reason	Textual Support
Gn04-22	Tuval-Kayin and Naamah	Tuval-Kayin, a tool provider, undoubtedly assisted Noach in the ark construction. Noach then married Naamah, Tuval-Kayin's sister.	None
Gn28-09	Nevayoth and Machalath	Nevayoth helped arrange marriage of Esauv and Machalath	The verse mentions the marriage of Esauv to Machalath, the sister of Nevayoth
Ex06-23	Nachshon and Elisheva	Nachshon resembled Aharon whom Elisheva married	The verse mentions the marriage of Aharon to Elisheva the sister of Nachshon
------	------	------	------
Ex16-20	Aharon and Miryam	Aharon interceded to protect Miryam when she was punished with Leprosy (Nu12-10:12)	Nu12-10:12 explicitly mentions Aharon interceding on behalf of Miryam
Gn34-25	Shimon and Levi, Dinah's brothers	They fought to protect Dinah	Gn34-25 explicitly mentions that Shimon and Levi declared war on an entire city where Dina's rape took place.

Advanced Rashi: Rashi at various points adds further details. For example on Ex06-23 Rashi states A person who wants to marry a woman should see if he is compatable with her brother since sisters resemble brothers closely. Our main goal here is to show the database aspect of these Rashis.

These Rashis do not appear that strong. In the last two examples we have explicit textual references to the brothers protection of the sister. Of the remaining three cases, two involve an explicit mention of marriage while one simply reports the brother sister relationship.

Thus the Rashi-midrashic suggestion that the brothers helped marry the sisters is seen as a reasonable generalization of the verses but certainly not explicitly indicated. This type of logic is a characteristic flavor of the database method. The strength of the derivation is based on the aggregate totality of examples most of which show the marriage-protection aspect underlying the database examples.

The serious student of Rashi should carefully study the above examples and convince themselves that the Rashi-midrash approach was the most reasonable.