Penurunan Jumlah dan Motilitas Spermatozoa Setelah Pemberian Ekstrak Biji Pepaya (Kajian Potensi Biji Papaya sebagai Bahan Kontrasepsi Alternatif) The Declining of Spermatozoa Number and Motility of Mice Were Treats with Papaya Seeds Extract (Department of Biology, Faculty of Mathematics and Sciences, Semarang State University . Ro, 2009)