caudoviral

Discussions and reflections on science and life

Archive for the ‘Sex, Sexuality, and Gender’ Category

While we are on the subject of sex differences…

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Females infected with HIV proceed to AIDS faster than their male counterparts. This is, ironically enough, one of the benefits of being a pre-menopausal female at work. As I explained earlier, there is a recognizable gradation in survival value between pre-menopausal females, males, and post-menopausal females based on reproductive capability. You can’t properly gestate a child for 9 months if you are dead. To this end there are several health benefits exclusive to the pre-menopausal female system.

Or rather, they would be benefits were it not for the nature of this virus. Now, in HIV’s defense, this is not actually of selective benefit to it. Viruses aren’t out to kill us and in fact doing so prevents them from going about their merry business of infecting more hosts. What happens is that the HIV latency period relies on its ability to go dormant in inactive immune cells, but in these female patients there is a generally higher level of immune activity. This means fewer inactive cells overall, fewer places for HIV to hide, yet unfortunately not enough immune activity to actually eradicate the infection. The end result is that the patient’s immune system takes more wear and tear than her male counterpart’s, the higher rate of cellular activity leads to higher viral activity, and she progresses to AIDS significantly faster.

Notably this sort of thing is also implicated in the higher rate of auto-immune disease in the female population.

Just as a note, you can probably expect a lot more HIV latency articles throughout the rest of the semester. Have just started research on it, I should be dredging up all kinds of interesting stuff from the literature.

Sources & Further Reading

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Written by Caudoviral

02/21/2011 at 09:06

Sex & the Myth of Gender

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So recently the lovely ladies over at Fishnet Bluestockings added me to their blogroll, and I have reciprocated in kind. If you are at all interested in a rational slant of feminism, especially as it concerns the entertainment industry, I highly encourage you to go check them out (and I am not just saying that because one of their writers is a dear friend). This post is inspired by something I started saying in their comment sections, and as it concerns something that influences my view on humanity in general, I thought it would be best to expound on it here.

Sex is a defined, binary, biological distinction. It is a genetic designation based on the possession of a particular genotype. In humans this is the presence or absence of the Y chromosome and even more specifically the gene SRY (Sex-determining Region Y).

There's the little bastard now (courtesy of the NLM).

In other animals it can get a little more complicated and fun, but that’s beyond the scope of this post. So, the presence or absence of this one thing is the difference between male and female. It’s a pretty tiny piece of genetic material, but then you know what those people with penises say… And (in this case) they are not too far off the mark. The cascade effects of having this are huge and make for a great deal of phenotype variation between males and females (for a good example of this, just check out my article on Estrogen, Leptin, and Obesity). Males and females are biologically and genetically geared towards different things: e.g. males store fat in different areas of their body, males create sperm instead of ova, males tend to have an easier time developing muscle, etc. There is also a great deal of structural change, bone shape, brain shape, there have even been recent studies showing a difference right down to the cytology of certain cell types, etc.

But what does all this mean? It means that biology is damn awesome, and it means that males and females have a number of legitimate differences that need to be taken into account if for no other reason than their medical significance. As a for instance, hip replacement therapy needs to be different for males and females since we have different bone structures in our reproductive regions (ironically there is currently only a single ‘sexless’ hip on the market because doctors have been accused of being evil and sexist for saying that their male and female patients need different prostheses). What this most emphatically does not mean is that one sex is somehow better than the other. This latter idea is part of the myth of gender, and is one that should be expunged.

Gender is a fuzzy, poorly-defined, spectrum with a basis in sociology and psychology. The important thing to take away here: GENDER IS NOT SEX. This would be a lot more clear if our society could stop marginalizing transgender individuals (and stop conflating the larger transgender community with strict transsexualism or any kind of display of sexuality). Now, gender would like to be sex, and for quite a while the enforcement of a narrow gender role based on biological sex has been the status quo (in recent years this has become less true for the concept of ‘woman’ thanks in large part to the feminist movement). The idea of gender is deeply ingrained and wants to survive and so it will often pretend to have a ‘natural’ basis. In recent years this has adopted the language of science and the lie that gender has a biological basis, or that indeed gender and sex are one. Both of these are easily shown to be false due to varied gender roles across culture and race, and especially by the presence of both eclectic third gender individuals (like your humble author and many American transgendered people) and organized third gender groups (like the Hijra). None of us have a fundamentally different biology than any of the normative folk walking around. None of us are not, at a genetic level, male or female. But we are most emphatically not men or women. And given how that false dichotomy has been repeatedly abused as the subject of a patriarchal power play, why would we want to be?

Written by Caudoviral

02/20/2011 at 16:52

Estrogen, Leptin, and Obesity

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Fair warning: the following is sexist in the way only evolutionary biology can be.

Females are, individually, more valuable than males. Until they hit menopause that is (at which point they become worthless). This is how our bodies work, don’t shoot the messenger. As manifestation and proof of this concept we can examine susceptibility to cardiovascular, cerebrovascular, and metabolic diseases. In order of least to greatest risk: pre-menopausal females -> males -> post-menopausal females. From the standpoint of passing on genes, it is important for females to be able to stay healthier for the span of time necessary to produce offspring, for as long as they are offspring production capable. After that point, the body stops caring. But don’t worry, scientists don’t.

Researchers like Deborah Clegg are working quite hard to understand what exactly happens at that crucial dividing line. The most obvious change? A stiff decrease in the amount of estrogen in the body. Okay, but how does that affect health? Glad you asked. I just had the pleasure to sit through a lecture given by Dr. Clegg, and it provided several fascinating insights:

1) Metabolic activity, hunger response, and eating behavior is largely controlled by a protein known as leptin.  When you give excess leptin to pre-menopausal females it prompts a dramatic change in their eating behavior (and possibly metabolism) that leads to weight loss. No such similar response exists in males or post-menopausal females. Interestingly, we have known about the general effect of leptin for ages, although the male/female divide is new info (New info that makes it seem pretty silly that when drug trials were done on leptin to see if it could be used as a diet pill they used an all male test group. Missed opportunity that.)

2) This sex-specific/age-specific behavior is because estrogen is a necessary co-factor in leptins function. Estrogen both is necessary for the transport of leptin across the blood brain barrier and the activity of nuclear estrogen receptors increases production of  leptin receptors. There are a number of ways to demonstrate how critical estrogen is to this, but perhaps the best is that if you give males or post-menopausal females estrogen injections, it allows for the response to leptin seen in pre-menopausal females.

3) Hormonal birth control can mimic some of the effects of menopause. By suppressing the normal ovulatory cycle and exchanging the peak of estrogen activity during ovulation for a regulated, lower estrogen level, the door is opened for the flood of nasties that most females shouldn’t have to worry about until after their child-bearing days are over. Indeed, Dr. Clegg’s data suggest that in the absence of prevalent hormonal birth control, there would be little to no obesity or obesity correlated illness among pre-menopausal females. Of course, my common sense suggests that there might be a little bit of a trade-off here, and that a few extra pounds could beat a baby in the cost/benefit analysis.

Afterthought (2/11/2011): Corrected some typos. It occurs to me that I should, for the sake of clarity, note that the above applies in mice/humans, it probably extends to other animals but probably not beyond mammals. Maybe not even beyond placental mammals.

Sources & Further Reading

  • Once again this is based on the fascinating research of Deborah Clegg, whose recent publication list is available here
  • Dr. Clegg will be appearing in a 2012 documentary on the obesity epidemic in America, although I was remiss in not catching the name.

Written by Caudoviral

02/11/2011 at 09:18