Glossary of Terms

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An abnormal dilatation of the veins surrounding the testes. A varicocele, present in 25% of infertile males, causes blood to pool in the veins of the testes. This pooling presents a problem for some men because the presence of excess blood raises testicular temperature, which can be detrimental to sperm. The surgical correction of a varicocele is minor, and performed in order to ligate the dilated vessels or veins. However, the success of treatment is controversial. Pregnancy rates after surgery are reported to be in the range of 30-50%.

Vas Deferens

The segment of the tube that connects the epididymis to the urethra in males.


A surgery to ligate the vas deferens in males, thus blocking the transport of sperm to the urethra. It is a very effective form of contraception that can be reversed. However, the longer the wait from the time that you have a vasectomy to the reversal surgery, the less your chances are of a successful pregnancy, due to the presence of anti-sperm antibodies.


An ultra-rapid method of freezing eggs and embryos that has led to a significant leap forward in the success of freezing of these tissues. Vitrification has allowed for the successful freezing of human eggs prior to fertilization, a process that was very poor with older freezing methods. Vitrification has also allowed for the improved survival rates of frozen-thawed blastocysts.