Opinion Conversations on the science of autism research.

Policy set to reduce gender inequality in biomedical studies

by  /  30 May 2014

The sciences have a long history of inequality and discrimination against women, and autism research is no exception. Female researchers — especially those in high positions — are still a minority in labs, and few studies enroll women with the disorder.

The gender bias even extends to animal models. Researchers favor males — whether rodent or cellular — over females for their studies. This tendency to err toward the male might skew results and ultimately affect clinical trial design and drug development.

The National Institutes of Health (NIH) has at last taken heed of this problem. A new NIH policy aims to eliminate gender bias in animal and cell-based biomedical studies, according to a commentary published 15 May in Nature.

Beginning in October, the agency will fund only experiments that use an equal balance of male and female cells or animals — unless a study explicitly and justifiably aims to investigate some sex-specific question. To help ease the transition, the NIH plans to hold training sessions for staff, reviewers and grantees.

The policy reform has several implications for autism research. As in most other biomedical fields, male animal models dominate research on both autism and related disorders such as Rett syndrome.

Scientists tend to avoid using female rodents, on the assumption that hormonal fluctuations in the females might alter their results. But that’s precisely why they should include the females.

A 2012 study reported, for example, that female mice of two difference genetic backgrounds serve as reliable animal models for Rett syndrome. The disorder primarily affects girls, whereas boys with the disorder die in infancy. Male rodents with the Rett mutation, likewise, tend to quickly exhibit severe symptoms and die young.

This does not reflect the experience of Rett syndrome in girls, who usually take months to show any symptoms. The female mice’s symptoms also appear later than the males’, and they live longer. In other words, the female mice are more consistent with how Rett syndrome manifests in girls.

Doesn’t it make sense to use the female models, then, rather than the male mice most labs rely on?

Studying only male rodents might similarly prevent researchers from understanding the crux of sex differences in autism.

A growing body of research supports the notion that what we know about autism in boys does not necessarily translate to girls. Studies have found, for example, that girls seem to have some level of protection from autism. And the disorder also looks different in girls than it does in boys.

More boys are diagnosed with autism than girls, at a ratio of about four to one. Some of this gender imbalance may be real, but evidence also indicates that many girls with autism go undiagnosed because their symptoms do not follow the male model. As a result, these girls miss out on potentially helpful treatments.

In 1993, the NIH passed the Revitalization Act, which mandated that research it funds must include girls and women. As a result, today more than half of the participants in NIH-funded clinical research are women.

The new policy will hopefully usher in a similar shift in the way basic research is conducted. Ultimately, the researchers write, this will help to “ensure that the health of the United States is being served by supporting science that meets the highest standards of rigor.”

  • ASD Dad

    It is an interesting concept and I can certainly see some real benefits. In autism we know that there are significant gender differences for instance ratio.
    Taking this further into exploration of male v female physiology , genetics , neurology and environment could well lead to specific interventions and dare I use the word ‘cure’ for core autism symptoms if not co-morbid conditions.

    It is further of interest that a recent poster presentation at IMFAR by a Stanford University research team examining ten co-morbid conditions (attention deficit hyperactivity disorder (ADHD), autoimmune disorder, bowel disorders, CNS/cranial anomalies, diabetes mellitus, epilepsy, inflammatory bowel disorders, muscular dystrophy, schizophrenia, and sleep disorders) found significant differences in prevalence rates in males than females and by age.

    For instance in inflammatory Bowel Disease there was a higher prevalence in males and in other bowel diseases the researchers report.

    “Notably, the prevalence of bowel disorders was highest in males in both the 0-18 and the 18-35 age range, then switching to higher prevalence in females in ages 35 and above. Similarly, schizophrenia was more prevalent in males 0-18 years of age, but then had higher rates in females in the 18-35 and 35 and above age ranges. ”

    Of course these types of findings may require a new reflection and re-examination on past research papers.

    One of the most ‘staggering’ findings was “Epilepsy, for example, decreased from a staggering 41.12% in ages 0-18 down to 24.43% and 15.15% in ages 18-35 and ages 35 and above, respectively; while remaining at a relatively consistent .8 – 1.8% in the non-ASD sample.”

    • passionlessDrone

      Fascinating finding. Thanks for posting it.

      Of course, the age differentials might not be so stunning if consider the possibility that we are *studying different phenomena in this generation of children*. That is an uncomfortable supposition for a lot of people, it seems.

  • ASD Dad

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