User blog comment:Cococrash11/Hollows breeds with humans/@comment-1454424-20100501133016

It is not stated that Arrancar CAN give birth. On the other hand, multiple shinigami were "born" in soul society.

It would be foolish to say something like "but since it doesn't explicitly exclude Arrancar from having children, they might". They cannot. For one, there is no proof that their body functions the same way as those of humans and shinigami. There is no proof that they have reproductive organs. They may all be Ken and Barbie dolls, if you know what I mean. In addition, since the concept of "birth" has only ever been present on the hollow side in the form of "destructive birth" - hollows eating pulses to turn them into hollows, hollowing eating each other and evolving etc, etc. It is safer to assume that they cannot reproduce in any "constructive" way.