Xenogenesis (n.):

1. The supposed production of offspring markedly different from either parent.
2. See alternation of generations.

• The American Heritage® Dictionary of the English Language, Fourth Edition. Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. More from Dictionary.

Xenogenesis (n.): the alternation of two or more different forms in the life cycle of a plant or animal.

• WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. More from WordNet.