Scientist in labInfertility is a growing problem for people around the world anxious to become parents. Studies indicate that, in the past 50 years, the number of sperm produced by the average man has dropped by about 50%, a factor that contributes to some forms of fertility impairment. A biotech company based in France has recently announced their ability to grow human sperm cells in the lab, a breakthrough expected to help many couples overcome male-related infertility issues.


Kallistem, headquartered in Lyon, describes itself as “a biotech company specialized in spermatogenesis . . . with the objective to anticipate and treat male infertility.” In early 2015, the company announced it had been able to accomplish spermatogenesis (creation — genesis — of sperm cells) by working with immature germ cells harvested from testicular biopsies of cancer patients.

From Lab to License

Germ cells are the specialized form of stem cells that become either egg or sperm cells. Immature germ cells have not yet differentiated (evolved) into either male sperm or female egg cells.

Building on knowledge acquired during similar animal studies, the Kallistem research team was able to coax immature germ cells from human testicular tissue into mature, functional sperm cells, an intricate process that takes 72 days.

Confidence in the company’s ability to achieve functional spermatogenesis is leading to a series of clinical trials to perfect the technique and gain regulatory approval in various markets around the world. Preclinical trials (using animal testicular tissue) currently in progress are expected to last into 2016. The first in a series of clinical trials (using human testicular tissue) will begin in 2017.

Kallistem is projecting a five-year timeline to begin marketing the technique to medical facilities working with assisted reproductive technologies. As the scientific work progresses, the company is working with licensing and regulatory agencies to ensure any final product that comes to market meets legal and ethical standards wherever it is sold.

Who Might Benefit

On a global scale, approximately 15,000 boys each year undergo medical treatments such as chemotherapy for cancer that damages the child’s ability to produce sperm when he reaches sexual maturity. The Kallistem spermatogenesis technique is expected to spare many of these young men from infertility in a four-step process:

  1. Extraction of healthy testicular tissue before toxic treatments begin.
  2. Cryopreservation (freezing and storage) of the tissue until the man is ready to father a child.
  3. Thawing and manipulation of the frozen tissue to produce viable sperm cells.
  4. Intracytoplasmic sperm injection (ICSI), in-vitro implantation of a sperm into an egg during an IVF procedure.

In addition to sparing fertility for young cancer patients, the Kallistem procedure may also enable men with non-obstructive azoospermia (NOA) achieve fatherhood. The company estimates more than 120,000 men experience NOA on an annual basis. The spermatogenesis process would work similarly with grown men but without the need for cryopreservation while the patient reaches adulthood.


  1. Kallistem. Kallistem, 2015. Web. 15 June 2015.
  2. Sheynkin, Yefim R. "Nonobstructive Azoospermia." Stony Brook Medicine: Patient Care. Kallistem, n.d. Web. 15 June 2015.