Berleigh, we're talking probability here, not causality.
Having your mother have a much more female siblings than the 50% ratio is either dumb luck or linked to something in the genes. Especially if
it also happened in the previous generation. Say, if your grandmother
had many sisters and few brothers.
2 sister 1 brother, could easily be dumb luck, but 10 sister, 1 brother is
very unlikely, if it happens over many generations, well there is
something happening for sure since it couldn't happen
Unless there is something systemic that happens in
reproduction.
That same something can seemingly expressed in
some of the male offspring and thus cause TS to happen
in some of them (substantial probability of occuring,
though not a certainty).
With people having less and less children
(since 1 or 2 children is not enough to get a really
skewed ratio), it will be harder to get
information from the current generation, though looking at
our ancestry could help.