when do males start growing sperm
Not at the very start, normally about half-way through. On average boys start puberty around 12 or 13 years of age. One of the first changes to occur is for their testes and scrotum to begin growing. The result of this is that most boys begin to produce sperm around a year after begining puberty, usually aged 13 or 14. But there is a great deal of variation and many boys start earlier or later than this.