Down syndrome is caused by a chromosomal aberration that comes about during formation of an egg, not a mutation. It's not possible to detect it by screening the parents' DNA.
PGT-A testing is very common in IVF and will catch Down Syndrome. Essentially no births from IVF (a growing percentage of all births) have Down Syndrome.
As you mention, this testing is done after an embryo has been created.
I've had many a conversation with women that have decided to not have kids. This is where I first heard of a fetus referred to as a parasite. I found it quite humorous. It's their body after all*, and if that's how they think of having some life form growing inside their body, I'm here for it.
* as recognized in fewer places
I have a theory as to a clustering of ideas, you could call it a worldview, but its hard to pin down or narrowly define. However, some aspects appear axiomatic; and when you call a baby a parasite, that is an indication that you may share this worldview.
Id be interested in discussing it further. What are its fundamental predispositions, what do you have to assume is correct to adopt this view? What is the point of society?
I would be happy to exchange information on anarchocapitalism if you are interested.
If we drop the species bit, and the negative connotations, it's not far off the mark. Children, in utero are certainly not symbiotic.
Just from a biological POV the toll on women for carrying children is HUGE. There's a whole swath of things that get rebuilt in a woman's body (nose/sense of smell being an interesting one) and a rather large tax on resources. Calcium is a huge one, most mothers in the west supplement as part of pregnancy. Dig deeper and you're going to find more and more biological impact that looks less (re)"productive" and more parasitic.
If you change domains to art, the whole film aliens covers the themes of rape, impregnation and parasitic child birth. These notions are not far from our fears and nightmares.
Lastly loving your children and being honest about a biological and personal toll they take are not incompatible. I know women who HAVE children they love and adore who have used the term parasite to describe the process they went through. It is done partly with tongue in cheek and partly to express something horrifyingly taxing on their bodies...
The rest of your statement says you do not understand why comedy and stress have the relationship they do.
If you go look there is data for the impact of humor on stress, on fear, on danger. The product of comedy, laughter, is one of the few autonomic functions that others can trigger in you.
In return I would caution you to not police others good time. Not only is it unfounded in data (yes there has been research on this, no one supports this perspective). It is the thing that has been done for generations, and failed (see tipper gore as the latest example).
>> dehumanizing comedy about blacks in the era of slavery or jews in the holocaust
Candidly this take is deeply misinformed. Blackface, had shades of slavery but the larger arc of it was NOT that. Calling attention to the slavery aspect is actually diminishing what it was. You're also reinforcing the stereo type of Black people and Slavery something that is massively historically inaccurate, read about the bakery pirates and the ottomans. Plenty of other people from other races have been slaves throughout history.
Meanwhile calling out "jews in the holocaust" and comedy is going to be a hard sell. Not only was this comedy never common, the foundations of American comedy are deeply rooted in the jewish community and jewish tradition. The godfather of modern comedy, Lenny Bruce was a jew. The scene in the Catskills that drove early days comedy that ended up on television (think cid cesar) was jewish.
"Embryo implantation sets off a process that ultimately turns off a key pathway required for the immune system to attack foreign bodies. As a result, immune cells are never recruited to the site of implantation and therefore cannot harm the developing fetus."
...
"it gives a satisfying explanation for why the fetus isn't rejected during pregnancy, which is a fundamental question for the medical community" - https://www.sciencedaily.com/releases/2012/06/120607142244.h...
Have a google around for similar papers. It's a fascinating topic that we've only begun to fully understand in the last decade or so.
If you seek to use this analysis to push a political agenda, then I am having trouble differentiating the morality between that and slave owners pointing to the shape of skulls based on race. Your explanation is an analogy, parasites dont grow up to eventually provide care for the host, it doesnt sound scientificially accurate to call a baby a parasite based on some of the characteristics. Further, calling a baby a parasite, or anyone for that matter, is an attempt to dehumanize them; dehumanization has been followed by violence in a number of horrific tragedies, but the violence is committed by people who find it justified, because whoever they are killing aren't really people.
edit: re-reading their comments, I'm at least 80% sure.
Though, the strategy isnt so much about winning in that arguement, but just trying to get an ugly response, so you are probably right.