TSPYL4 and male infertility: The TSPY genes are a superfamily that includes TSPYL1, TSPYL2, TSPYL3, TSPYL4, and TSPYL5. There are no studies reporting a biological explanation of the relationship between the TSPYL6 gene and male infertility, but two studies demonstrated that allelic variants of the TSPYL1 gene might be associated with isolated gonadal dysgenesis or anomalies of the spermatogenesis that could cause abnormal production of spermatozoa [55,56].