In addition, it is thought by many that the mathematical system found on the Ishango Bone (now hijacked by Belgians and put into their "Royal Institute for Natural Sciences" of Belgium in Brussels) was created or done by women because of its lunar bearings. This bone comes form the Zaire/Ugandian area. It is dated at least to 25,000 years ago.

This information comes from the same site quoted below in the article you have posted. I think that it is pretty plausible.