Male germ cells transcribe an unexpectedly large portion of the genome, including typically silent repetitive elements, but the purpose of this widespread transcription has been unclear. A new study shows that the heterochromatin protein HP2 is required to drive transcription of AAGAG satellite DNA in Drosophila spermatocytes. Loss of HP2 prevents proper remodeling of heterochromatin, leading to persistent repressive histone marks and failure of sperm DNA packaging, ultimately causing spermatid death. Strikingly, this defect disproportionately affects spermatids carrying the Y chromosome, which harbor more AAGAG repeats, resulting in a sex-ratio distortion. Together, these findings suggest that transcription of satellite DNA facilitates chromatin reorganization during spermatogenesis and reveal how variation in repetitive DNA content can bias gamete survival and drive meiotic conflict.