In this age of technology, we
tend to believe technology surpasses human capability. Research constantly
disproves by brining to light certain biological processes and natural systems,
which are way, better, accurate and also in many cases profitable. One such
example being the ability of mammals to choose the sex of their offspring.
A new breakthrough study
conducted by a research team at Stanford University School of Medicine recently
revealed how female mammals could manage to determine the sex of their
offspring by controlling the sperm while it travels through her body. The study
also claims that this mechanism could be responsible for mammals having an
increased chance of having more grandchildren.
The researchers took in breeding
records of 40,000 mammals spread over a period of 90 years. Joseph Garner,
Associate Professor of Comparative Medicine and senior author of the study
explained, "This is one of the holy grails of modern evolutionary biology -
finding the data which definitively show that when females choose the sex of
their offspring, they are doing so strategically to produce more
Careful analysis of three
generations of more than 2,300 animals revealed a shocking discovery that the
mammals were able to strategically choose to give birth to sons. Joseph Garner
further added, "Amazingly, the female is somehow picking the sperm that will
produce the sex that will serve her interests the most: The sperms are really
just pawns in a game that plays out over generations."
These findings seem to in some
ways coincide with the theory proposed by scientists Dan Williard and Robert
Trivers in 1973, who believed that mammals manipulated the sex of their
offspring such as to maximize their reproductive success.
Although the exact mechanism
behind this manipulation is yet to be known correctly, it is speculated that
the female mammals are able to control the 'male' and 'female' sperm within
their bodies, which are differentiable owing to the difference in their shapes.
The females are able to speed up or slow down the sperm they want to select.
The findings of this study are published in PLOS ONE.