Attack of the clones, not the movie.

Common greeting,

Spark....spark....inhale....exhale....calm blue ocean...Ok Gents and Ladies, heres the problem;
a friend of mine has made 100 clones from 6 suspected mothers, all rooted. later on it was found out that 1 of the heavily cloned 'mothers' was a father.

It could be up to half of all the clones are male, which would be an efficient yet non-sacrificial, disregarding the males, way of determining sex? Space is a consideration, as is time. Any help is much obliged, many thanks to all!