But--heck! It is possible for it to land on edge and stay there.
What if technology is developed that makes it highly probable that the coin will successfully land on its edge repeatedly with a frequency sufficient to establish a general idea of just how likely it is?
But, really, there is no natural mechanism possible for asexual reproduction among humans. Human reproduction without sex and without technological intervention is not possible; for this to ever happen it would be more like a perfect sphere landing perfectly balanced on one of its four corners.
The fact is, if it did happen, it happened due to technological intervention. The ubiquitous presence of extra-human interactions found in the descriptions of human conception without sex do not point to anything conflicting with technological intervention.
Anomalous interactions with humans by extra-human sources would prove a rule, too, would they not, Terry?
Respectfully,
AuldSoul