Many andrological pathologies seen in adults, including infertility, actually arise at a younger age, due to the strong susceptibility and vulnerability of the male gonad to external insults, starting from age of gestation and during all growth phases. Although three main phases are particularly susceptible for subsequent normal testis development and function (the intrauterine phase, the neonatal phase comprising the so-called “minipuberty”, and puberty), even during infancy, when the testes are apparently “sleeping”, damaging causes with permanent effects on testicular function can occur. Since a great number of risk factors for future male fertility might already be present at young ages, the possibility for early diagnosis and prevention of negative sequelae is unfortunately low if systematic health and information programmes are lacking. Indeed, interventions focused on childhood and adolescence could have a profound effect on sexual and reproductive health later in life. To do this, multiple level interventions are necessary.