Testicular germ cell cancer (TGCC) shows a strong genetic disposition, with the most significant gene variants being those linked to gonad formation and germ cell function. Environmental
Exposure of a male fetus to substances that disrupt hormone systems, particularly chemicals that inhibit the action of androgens (male sex hormones) during the development of the reproductive system, has been shown to cause many of the characteristic TDS disorders. These include environmental estrogens and anti-androgens found in food and water sources that have been contaminated with synthetic hormones and pesticides used in agriculture. In historical cases, medicines given to pregnant women, like diethylstilbestrol (DES), have caused many of the features of TDS in fetuses exposed to this chemical during gestation. The impact of environmental chemicals is well documented in animal models. If a substance affects Sertoli and Leydig cell differentiation (a common feature of TDS disorders) at an early developmental stage, germ cell growth and testosterone production will be impaired. These processes are essential for testes descent and genitalia development, meaning that genital abnormalities like cryptorchidism or hypospadias may be present from birth, and fertility problems and TGCC become apparent during adult life. Severity or number of disorders may therefore be dependent on the timing of the environmental exposure. Environmental factors can act directly, or via epigenetic mechanisms, and it is likely that a genetic susceptibility augmented by environmental factors is the primary cause of TDS. Lifestyle
Links between maternal smoking and TDS are tenuous, but there are stronger associations between maternal alcohol consumption and incidences of cryptorchidism in sons.
Testicular dysgenesis syndrome is a male reproduction-related condition characterized by the presence of symptoms and disorders such as hypospadias, cryptorchidism, poor semen quality, and testicular cancer. The concept was first introduced by N.E. Skakkaebaek in a research paper along with the department of Growth and Reproduction in Copenhagen University. The paper suggests the origin and underlying cause of TDS can be detected as early as in fetal life, where environmental and genomic factors could affect the development of the male reproductive system. Causes
Central to the cause of irreversible TDS are disruptions to early fetal testes development. This has genetic, environmental, and lifestyle components, however the rapid increase in the incidence of the disorders associated with TDS in the last decades indicates that it is under a powerful environmental influence. The fetal origins of TDS are reinforced by the high incidence of TDS disorders found occurring together in one individual. Associated with mutation of Insulin like Factor 3 (INSL3)

Genetic
Many genes have been implicated in the disorders of TDS, with genome wide association studies (GWAS) regularly identifying new gene variants that play a role in abnormal testes development. Some of these are specific to certain disorders, and some are part of a risk factor network that connect TGCC, hypospadias, cryptorchidism, poor semen quality. The majority of these genes are involved in fetal gonad development. Mutations in androgen receptor genes are highly implicated, as these are involved in penile development, testes descent, and testes development.