Besides genitals, body organs are also male or female

It is not just the reproductive organs in human that appear to have a sex. Other body parts too seem to indicate that its owner is a male or female.

The gender of an organ may explain why certain diseases, such as cancer, hit more one gender. This differentiation could possibly also explains why male and female body parts respond differently to the same treatment, says a study published in Nature journal.

In some organs, such as the kidney or pancreas, it has been known that these body parts function differently because of the circulating hormones. To determine if cells of organs know it belongs to a male or female body, researchers at the Medical Research Council’s (MRC) Clinical Sciences Centre at Imperial College London studied stem cells in the intestine of fruit flies.

The researchers turned “on” and “off” certain genes in the flies’ cells, enabling them to tailor the cells to be more female or male. They found that the process changed the way the cells multiples. The feminised cells multiplied faster than the masculinised cells, reports Medical New Today.

The stem cells of a female fly, when masculinised in the intestine of an adult fly, the gut shrinks within three weeks to the size of a male gut, reveals Dr Bruno Hudry, first author of the study. Meanwhile, female intestine was more prone to genetically induced tumours. The scientists believe the reason behind it is female must be more adaptable so they could cope with reproduction, causing them to be more susceptible to tumours.

But the cells that are feminised or masculinised could be reversed by modulating the activity of the genes, but it does not affect the overall organismal sex or hormonal sex of the fly. Manipulating the genes responsible for that sexual identity could change the way the organs behave, but it does not affect the body part’s development of the circulation of hormones, adds Hudry.

This discovery explains what makes male and female physiology different, says Dr Des Walsh, also from MRC. Hudry likewise points out that sex could be defined on different levels. These are organismal sex, tissue sex, cellular sex and chromosomal sex.

He says, “This study shows that there is a wider spectrum than just two sexes. You can be chromosomally, hormonally or phenotypically female but still have some specific adult stem cells (here the stem cells of the intestine) acting like male. So it is hard to say if someone is “really” male or female. Some people are simply a mosaic of male and female cells within a phenotypically ‘male’ or ‘female’ body.”

Hudry says that the finding, if confirmed in humans, would affect medical interventions such as transfusions and organ donations. The interaction between the sex of the donor cells, of the host and type of stem cells transplanted could affect the success of the stem cell transplantation. Understanding the difference could enable researchers to develop more effective therapies, notes Econotimes.

Study on humans would have implications for cancer development and how males and females respond to treatment, he says. The research comes at a time that gender-specific organs such as the uterus or penis are being tried in pioneering surgeries and transplants.