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Nancy L. Brackett, Ph.D., HCLD

Voluntary Professor, Departments of Urology and Neurological Surgery

Research Interests

Male Fertility following Spinal Cord Injury

Nancy Brackett, Ph.D.
Nancy Brackett, Ph.D.

The research in my laboratory is focused on understanding and improving the impairments to male fertility which occur following spinal cord injury (SCI). Following SCI, most men, but not women, experience impaired fertility. Specifically, most men with SCI are anejaculatory, and some experience erectile dysfunction. Although their semen may be obtained by medically-assisted ejaculation procedures, in most cases, semen quality is impaired, specifically, sperm motility and viability are abnormally low, although sperm numbers tend to be normal.

Our research is focused on determining the cause of impaired semen quality in men with SCI. Our studies have shown that factors secondary to SCI are not responsible for impaired semen quality in men with SCI. For example, the condition is not due to scrotal thermoregulatory dysfunction, the method or frequency of ejaculation, the number of ensuing years post-injury, or hormonal alterations. Our recent evidence indicates that the problem is related to the seminal plasma. For example, seminal plasma of men with SCI inhibits sperm motility of able-bodied men. In addition, sperm motility is much higher in men with SCI before the sperm mix with seminal plasma. Substances within the seminal plasma are abnormal in men with SCI, including elevated reactive oxygen species, decreased prostate specific antigen (a marker of prostate function) and decreased fructose (a marker of seminal vesicle function). The semen of men with SCI contains an abnormally high number of non-spermatozoon cells, most of which are leukocytes. Our current research is investigating inflammatory factors as contributors to the problem. Our ultimate goal is to develop therapies to normalize semen quality in men with SCI, so that chances of biological fatherhood are increased.

In addition to our investigation of the seminal plasma, we are studying methods to improve semen retrieval and semen processing for assisted conception procedures. Recent improvements treating male infertility in the general population have led to a problem for men with SCI. Often, their ejaculates are not examined as a source of sperm for assisted reproductive technology (ART). Instead, sperm are retrieved surgically from their testes or epididymes as a first line treatment for anejaculation. This development has resulted in many centers performing expensive and invasive ART to overcome the low sperm numbers typically obtained with surgical sperm retrieval. Our research is focused on optimizing non-surgical methods of obtaining sperm from men with SCI. By maximizing the total motile sperm available for ART, couples have a wider range of options for pursuing assisted conception. Our research is leading the field by establishing standards of care for treatment of infertility in men with SCI.


Nancy L. Brackett, Ph.D., HCLD

  • The Miami Project to Cure Paralysis
    1095 NW 14th Terrace (R-48)
    Miami, FL 33136
  • (305) 243-7108
  • (305) 243-3913



Male Fertility Following Spinal Cord Injury Update (03/15/2018)

Dr. Brackett Published Paper in the Journal of Spinal Cord Medicine (5/4/2017)

Miami Project Scientists Publish on Reproductive Health of Men with Spinal Cord Injury (4/13/2017)

Dr. Nancy Brackett Publishes about Male Infertility after SCI (02/17/2017)

Clinical Study Spotlight: Male Fertility (07/09/2014)


American Society for Reproductive Medicine
Society for Male Reproduction and Urology
American Urological Association
Society for the Study of Male Reproduction
American Society of Andrology
Society for Neuroscience
American Association of Bioanalysts
College of Reproductive Biology



Fertility and Sterility


Asian Journal of Andrology