The plot thickens:

This Fish Just Gave Evolution the Finger and Got Pregnant

Excerpts:

"Researchers aren't sure exactly how Mary, who is now dead, ended up pregnant this way, given that sticklebacks like her don't have sex with each other. One possibility was that she had cloned herself, and another was that she was a hermaphrodite and so had fertilized her own eggs. But genetic analysis revealed that her babies had two separate parents.

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Part of what makes the find so remarkable, the researchers said, is that under normal circumstances stickleback fathers play a necessary role in egg development beyond providing sperm. After taking over a nest of eggs, the fathers fan them with their fins as the eggs develop, stimulating healthy development processes. Something about the environment inside Mary seems to have done that job just as well. [The 7 Biggest Mysteries of the Human Body]"