As the age of the fetus progresses, differentiation begins. In the male genus, the inner region (the bone) grows from the neutral, primitive or undifferentiated genitals. The number of primary sexual cords increases, so that the pulp fills, the cortex becomes smaller and the primary sexual cords become hollow structures containing primary germ cells. Primary spermous tubules grow inside the primary germ cells forming semen. Thus, the testis, which is the first characteristic of the knowledge of masculinity.
