I suppose that there may be two basis for this, one biological and the other economical.

Biological--to make sure that only one's biological material is being passed along and that one does not consume valuable, and scarce, resources to preserve another's DNA line.

Economical--pretty much the same as above, plus it is a device preserve that property does not pass (through inheritance) to the "wrong" DNA line.

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Current Benzes

1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"

Res non semper sunt quae esse videntur

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