[bh23ha]

There are very small differences in terms of wealth, health care access, or even physical location between these two countries.

Or cultural traditions like

Mărţişor: http://en.wikipedia.org/wiki/M%C4%83r%C5%A3i%C5%9For

and

Martenitsa: http://en.wikipedia.org/wiki/Martenitsa

Or ancient history, or recent history, or genetics, etc.

This really makes me wonder about the study, and exactly what they measured?