Sperm can be frozen using cryogenics.
The answer to the question, "how long do sperm live?", is important to anyone involved in sexual activity or interested in donating to a sperm bank. While just one sperm is needed to fertilize an egg, an average of one teaspoon of semen is released upon ejaculation that contains up to 300 million sperm. According to the University of Pennsylvania Health System, only an estimated 200 sperm will live to reach the egg. The actual sperm count and health of the sperm are dependent on several factors.
Healthy sperm must have an oval head with a long tail to move on their own and make the journey to the egg. Because estimates on the lifespan of sperm are based upon healthy and viable sperm, chances of conception and the length of time sperm will survive can be greatly increased by taking measures to ensure that sperm is healthy and produced in adequate amounts.
Sperm are sensitive to higher temperatures, and therefore they are produced and stored in the testicles, outside of the body, where they are kept at a temperature 3.6 degrees lower than normal body temperature. If a mans testes do not descend or undescended testes are not surgically corrected, the warm temperatures inside of the body can be enough to cause sterility. In fact, a man can reduce his sperm count by simply taking too many long, hot baths.
Eating a balanced diet, taking a daily multivitamin, exercising regularly, reducing stress and keeping a healthy body weight are the most important steps to increasing the viability of sperm and will insure that they live as long as possible. According to the Mayo Clinic, the health of sperm can be further protected by:
In the male reproductive system, sperm are produced in the testes at the rate of about 12 billion sperm per month. The maturation and migration process takes about 20 days from beginning to end after which sperm are stored in the epididymis, or the coiled tubules located above the testes inside of the scrotum.
During the process of ejaculation, matured sperm move out of the epidiymis and through the narrow tube of the penis, called the vas deferens, and pass through ejaculatory ducts. In these ducts, sperm mixes with seminal fluid, a high-fructose, alkaline substance that not only acts as fuel for the sperm, it also protects them from the acidic environment inside of the vagina.
From the ejaculatory ducts, sperm and seminal fluid pass through the prostate gland where it is mixed with a milky prostatic fluid that helps the sperm to swim more easily. The final mixture, known as semen, is ejaculated from the urethra.
Because the lifespan of sperm is dependent on a number of factors, estimates can vary greatly. According to the University of Michigan Health System, normal sperm have an average lifespan of about 4 days; however, cases have been reported in which sperm has effectively fertilized an egg 6 days after intercourse.
In healthy males, only 50 to 70 percent of sperm are viable at the point of ejaculation. If exposed to air, the remaining living sperm will die in just a matter of minutes. Sperm that are ejaculated into the female body face another set of obstacles that vary depending on the womans menstrual cycle.
Prior to ovulation, the female body begins to prepare for the introduction of sperm by maintaining a lower body temperature and producing an alkaline cervical mucus. In this sperm friendly environment, sperm may live between 3 and 5 days; however, when this fertile mucus is not present or basal body temperature has risen after ovulation, sperm may only live between 24 and 48 hours. It is important to remember that the fertile cycle of women will vary greatly from one individual to another, which in turn will affect the lifespan of sperm inside the body.
Attempts to keep sperm viable through freezing began in the 1950's and science has now found a way to greatly increase the lifespan of sperm, allowing for conception through artificial insemination using frozen sperm. As soon as possible after ejaculation, semen is combined with cryoprotectant agents, or agents that protect the sperm during both freezing and thawing. Cryoprotectants are generally composed of glycerol, egg yolks and other buffers, and are added gradually as the sperm is slowly frozen. On average, about 60 to 80 percent of frozen sperm will maintain health and motility after thawing, even if stored for 10 years or longer. Studies at the University of Berkeley have demonstrated that conception through the artificial insemination of frozen sperm takes, on average, 6 to 8 months.