type A spermatogonia spermatogonia English spermatogonia spermatogonia en spermatogonium spermatogonium English spermatogonium Spermatogonium spermatogonia http://en.wikipedia.org/wiki/Spermatogonium English spermatogonia en spermatogonia spermatogonium spermatogonia English English English type B spermatogonia spermatogonia spermatogonia spermatogonium English Spermatogonium spermatogonia English