What is an embryo? An embryo is a product obtained by fertilizing a female egg with male sperm. The sperm may be from embryo recipient’s husband or any other man whose identity is confidential. The man donating sperm is advised to undergo essential tests before donation in a situation where the man donating sperm is not known to the female recipient, but she may specify to the doctor, the basic demographic characteristics such as caste, religion, educational background, etc.