Required during spermatogenesis for normal chromosome synapsis and meiotic recombination in germ cells. Necessary for formation of DMC1 and RAD51 foci on meiotic chromosomes, suggesting a specific role in DNA double-stranded break repair (By similarity). Essential executor of PIWIL4-piRNA pathway directed transposon DNA methylation and silencing in the male embryonic germ cells (By similarity). PIWIL4-piRNA binds to nascent transposon transcripts and interacts with TEX15, which may in turn recruit the epigenetic silencing machinery to the transposon loci (By similarity). Not required for piRNA biosynthesis (By similarity). . This is the function of TEX15 (testis expressed 15, meiosis and synapsis associated, ENSG00000133863).