The Mom and Pop Team

From time to time, I think we all need reassurance that we matter. That our seat at the game has not been taken by someone else. Could not be taken… Maybe that’s why we’re given names -so there’s no mistake. And if we’re not there all the time, it’s only because we sometimes have other duties to perform.

In many species, the male role in procreation can seem like that, I suppose: a postal service that’s only charged with delivering letters, not reading them, not dealing with the contents. At least that’s how it looks from across the street. On closer inspection, though, it would seem that the delivered mail is far more complex than it first appeared. It’s almost as if whoever reads the letter not only sees the blueprint, and the construction manual, but much like reading a newspaper, also learns of other important things which, at first glance seemed unrelated, but in the end, profoundly affect the building.

These processes would obviously be difficult to study in humans, so often we have to model them in other species and extrapolate the results to our own kind. Two articles in the Smithsonian magazine outline some of this information.

There are at least two time frames when the male influence on the resulting offspring was unsuspected: before conception -in fact, even before meeting his potential mate- and during growth and development of the fetus, and even its neonatal care. The how is interesting, but equally so is the why, I think.

First, let’s consider the production of sperm in isolation from its immediate need.

Sperm are produced in the testes, and then travel to a storage area via the epididymis -a long, wriggly 6 meter long tube in the human. It’s in the epididymis that the sperm mature and become motile. ‘As sperm traverse the male reproductive system, they jettison and acquire non-genetic cargo that fundamentally alters sperm before ejaculation. These modifications not only communicate the father’s current state of wellbeing, but can also have drastic consequences on the viability of future offspring.’ Sperm contain genes, of course, but simply having the instructions doesn’t mean they will be carried out. Genes can be turned on, off, or down, by other mechanisms –epigenetics. ‘One of the most powerful members of the epigenetic toolkit is a class of molecules called small RNAs. Small RNAs can conceal genetic information from the cellular machinery that carries out their instructions, effectively ghosting genes out of existence.’ The father’s previous diet, stress levels, and so forth can all have an effect on these small RNAs, and the small RNAs are in turn shed or reacquired as the sperm continue their journeys along the epididymis.

And then, as I mentioned, there is an effect on the developing embryo whether or not the male is actively involved with the female during her gestation or in the subsequent rearing of their offspring.  Although the data is from mice, it turns out that ‘The paternal genes a fetus carries can impact the maternal brain during pregnancy, priming her to allocate more or less of her time to tending to her kids.’

‘A child that procures as many nutrients as possible from mom can secure a father’s lineage at no cost to him—but a mother still needs to prioritize her own wellbeing during pregnancy and early childcare.

‘This sexual conflict is well exemplified by a gene called Igf2, which drives the rapid growth of fetal cells. Like most of our genetic material, Igf2 is inherited in pairs—one copy from mom and one copy from dad. But in contrast to other genes, only the version from dad gets put to work. The Igf2 from mom, on the other hand, is stifled through a chemical modification that acts like a muffler on an engine. Mom’s Igf2 DNA undergoes no changes—but the gene’s instructions can no longer be heard over the din of the cellular milieu. […] If an error occurs that also switches on the mother’s copy of Igf2, the baby quickly balloons in size. This could be good news for dad—a big baby is more likely to survive—but mom can get in serious trouble if she has to carry and birth an unmanageably large fetus.

‘To guard against this possibility, females have developed their own failsafe: another gene called Igf2r. The “r” stands for “receptor”: the product of this gene can sop up free-floating IGF-2 proteins before they exert their growth-promoting effects. Unsurprisingly, dad’s copy of Igf2r stays quiet. Such is the phenomenon of genomic imprinting—a form of non-genetic inheritance in which both copies of a gene exist, but only one parent’s version is left intact. Over 150 imprinted genes have been confirmed in mice, about half of which have conserved counterparts in humans.’

Suffice it to say that there are several other paternal genes that code for growth or neonatal behaviours that can affect the mother’s response and subsequent care of her offspring -a kind of effect that evolution has decided would be in the best interests of all concerned.

For example, ‘expression of an imprinted gene called Phlda2 in a fetus hinders the growth of hormone-secreting placental cells. These hormones recruit nutrients to support early development. Unsurprisingly, the offspring’s paternal copy of Phlda2 is kept under wraps. But mothers want their copy to remain switched on. […] Other researchers had noted that these hormones weren’t just working in the placenta, however. Throughout pregnancy, they were actually spreading throughout the mother’s body and accumulating in her brain—leading John [professor of biology at Cardiff University] to suspect that they could also be encouraging a mother to care for her young. […] The team’s work lends credence to the idea that fathers don’t dictate the health of children through genetic inheritance alone. In cases like these, they can even utilize the fetus as a chemical envoy in this battle between male and female, swaying a mother’s priorities towards more attentive childcare.’

During many of the years when I was in active practice of obstetrics, I often felt I needed to be an apologist for the father who did not have to suffer the many exigencies of pregnancy, not to mention the difficulties of labour and delivery. Clearly, after fertilization, his role in the process seemed merely supportive, and often peripheral.

Were I to start my career over again, though, perhaps I could put in a louder word for the importance of our male side -although I’m not at all sure mom would be listening as intently at the end.


Scrambled Eggs

Great! Test tube mothers now, is it? Not enough to eliminate the Fallopian tube, or the on-egg dating site where potential sperm candidates meet, are scrutinized, profiles scanned and competition held for first across the zona (pellucida, that is) … Oh no, now we have to eliminate the entire coffee shop. What is happening out there… or do I mean in there? It’s so confusing.

There was a time when it was simple. Well, maybe it wasn’t, but at least we were used to it. You met somebody and expectations and hormones took over. No need to put in a special request for stem cells, or people in white lab coats and masks. No need to take out a loan –although flowers and dinners aren’t that cheap anymore, either. But it was the excitement of the chase, the hunt –searching for clues about the other person that weren’t all tied to their DNA; picking them because they were funny and considerate, cute and snuggly. They had histories. Stories. Isn’t that why we get together? Wasn’t it?

Okay, I’m leap-frogging here. We’re not there yet –I mean they are not there yet; I suspect that, despite the occasional slip-up, most of us are still going to prefer to stick to the traditional court-and-impregnate model that has served us so far. I mean, fun is fun, eh? And to be fair, there’s a lot to deal with if you want to bypass natural stuff -ingredients, for example. Right now, you need a minimum of two things to make babies: a sperm and a receptive egg (sperm always seem to be in the mood…). Yes, and you need a place for them to meet and grow together, but there are any number of uteri out of work at any given time, so, with the rise of things like Airbnb, I suspect they won’t be a problem.

And everything that is alive has DNA and its instruction manuals closeted away somewhere… Do you see the opportunities I’m suggesting? Trick some skin cell, or whatever, into thinking it’s a sperm or an egg, and poof –reproduction-lite. Better still, why not hoodwink that ordinary cell into thinking it’s pregnant? I mean, it’s got all the necessary assembly instructions squirrelled away, hasn’t it? Your argument just has to be convincing. Persuasive. It doesn’t necessarily need to be, well, necessary. You could just be doing it for fun. A prank. Or to prove that you can, I guess. Isn’t that why a lot of stuff gets done? When you tire of trying to justify something that would fly in the face of current needs and desires, you simply create a niche product. Create a want. Wants usually evolve into needs –mutate into needs, at any rate. Look at Selfies and their requirement for sticks. Or bell-bottomed trousers –no, wait, that was a while ago…

My point, I think, is that gender may be rendered redundant not by increasing social awareness of its variations, but rather because of its dispensability. Why keep something you don’t really need? History will decide, of course, but hindsight tends to come down hard on things that outlive their time. Consider phlogiston. It was the postulated fire element that was contained by combustible things and was released when they caught fire. Of course! But who, apart from old people, have even heard of it? Or want to?

And then, in keeping with the air theme, there is the Miasma Theory which just assumed that disease was caused by ‘bad air’. Simple. Elegant. No need to bring in a lot of accessory stuff like animalcules and other things you couldn’t see anyway. Germs, let alone viruses prions and the like, were simply unnecessary and unduly complicated. Why dump many unknowns into an equation that could be solved by one charming known? Why mess with E = mc 2 when it isn’t a theory of everything, especially if it needs Quantum? Explanation isn’t everything, either…

Okay, so I’ve non sequitured again, but hopefully you see my concern. Obsolescence is one thing –we often persist past our best-before dates- but unplanned obsolescence is another creature entirely. It smacks of blundering about in dark corners hoping there are no unpleasant surprises -nothing that will sting in retrospect.

I am as excited as the next person about the prospects for the future, but experience teaches caution. The principle of unintended consequences is a favourite historical topic –almost as seductive as the ‘what if’s’ so popularized in historical fiction nowadays. Maybe there is nothing enchanted about that first introduction between egg and sperm. Nothing magical. Nothing necessary. Maybe life will carry on much as before and procreation will still scratch out a living between the sheets. And maybe it’s always good to have options -choices freely made and understood. Even needed, occasionally. We have always been condemned to live in interesting times –the Past was never an Eden.

And yet…