Gonads are the organs producing offsprings. They are testis in male and ovary in female which produce sperm and ova respectively. It is not appreciate to remove healthy organs for the use of contraceptions. This can cause physical, mental and behavioural issues, while contraceptives are easily available and has no/least side effects. These are also not so costly, friendly users and can easily remove on requirement.
Removal of gonads is a complex process and legally banned. It is, therefore, not considered as a contraceptive option.