No outsider has ever seen a Tleilaxu female and survived to tell about it. Considering the Tleilaxu's tendency for genetic manipulation—see, for example, related memos on sligs, clones, and gholas—this simple observation raises a multitude of additional questions.

One of their most notorious creations is the ghola, a clone generated from the tissue of a deceased human and grown in one of their grotesque axolotl tanks. This allows grieving families to see their fallen loved ones once again—an expensive contrivance that makes the grim, gnomelike Tleilaxu extremely wealthy, although they will never be granted Great House status.