To further confirm the hypothesis that both Sertoli cells and spermatid cells are needed to express PD‐L1 to induce spermatid sloughing and infertility in TgPD‐L1 mice, we constructed another transgenic vector that coexpressed PD‐L1 and EGFP under the promoter of protamine 1 (P1), which was shown to be translated at spermatid stages during development35 (Figure 4D). This evidence concerns the gene PRM1 and Infertility.