Orchidometer

The orchidometer was introduced in 1966 by Swiss pediatric endocrinologist Andrea Prader of the University of Zurich.

[1] It consists of a string of twelve numbered wooden or plastic beads of increasing size from about 1 to 25 millilitres.

Doctors sometimes informally refer to them as "Prader's balls", "the medical worry beads", or the "endocrine rosary".

Discrepancy of testicular size with other parameters of maturation can be an important clue to various diseases.

Large testes (macroorchidism) can be a clue to one of the most common causes of inherited generalised learning disability, fragile X syndrome.