[DrN (OP)]

I've heard of couples struggling for a baby for years, with no obvious problems, yet as soon as they split up and remarry the babies just keep on coming!

A theory is that some couples are incompatible, so individually they are completely fertile, but will not produce offspring with one person whereas they will with another.

anyone know why?

[bezoar]

There are some instances of the female being allergic to her spouse's sperm...

[DrN (OP)]

so maybe its an immunity thing? although I thought the theory behind that was that we're supposed to be attracted to people with different immune systems (or whatever, not my field) so that the offspring would have a lovely variety of immunoglobulins to fight against infections.

[MooseHole]

Even if the "lovely variety of immunoglobulins" thing is true, there are some immunities that should not be passed on, such as immunity to sperm.  Not getting pregnant because you're immune (or allergic) to sperm is a healthy evolutionary phenomenon.  Although I guess it would be good to be allergic to sperm with HIV in it or something.

[neilep]

quote:Originally posted by MooseHole

Even if the "lovely variety of immunoglobulins" thing is true, there are some immunities that should not be passed on, such as immunity to sperm.  Not getting pregnant because you're immune (or allergic) to sperm is a healthy evolutionary phenomenon.  Although I guess it would be good to be allergic to sperm with HIV in it or something.

 Hi Moosehole

...did you mean that ? (in bold above), in the former sentance you say being immune to sperm should not be passed on.

Surely being immune to sperm could spell the end of humankind if it became a global phenomenon. I realise that it's a nigh on impossibility...but not a definite impossibilty.

I can't see how being immune to sperm is a healthy evolutionary phenomenon.






'Men are the same as women...just inside out !'

[neilep]

quote:Originally posted by bezoar

There are some instances of the female being allergic to her spouse's sperm...

Nance, in the cases where a female is allergic to her spouses sperm are there any symptoms ? (besides not becoming pregnant), and is it a treatable condition ?


'Men are the same as women...just inside out !'

[MooseHole]

quote:Originally posted by neilep

quote:Originally posted by MooseHole

Even if the "lovely variety of immunoglobulins" thing is true, there are some immunities that should not be passed on, such as immunity to sperm.  Not getting pregnant because you're immune (or allergic) to sperm is a healthy evolutionary phenomenon.  Although I guess it would be good to be allergic to sperm with HIV in it or something.

 Hi Moosehole

...did you mean that ? (in bold above), in the former sentance you say being immune to sperm should not be passed on.

Surely being immune to sperm could spell the end of humankind if it became a global phenomenon. I realise that it's a nigh on impossibility...but not a definite impossibilty.

I can't see how being immune to sperm is a healthy evolutionary phenomenon.

What I meant to say is that if someone is allergic to sperm, then this allergy has a less likely chance of being propogated to the next generation (this person may not have kids).  Not having kids is a way for things that shouldn't be passed on to not pass on.

[chris]

HIV isn't propagated inside the sperm, it's in the semen, alongside the sperm.

Immunity is not something that you inherit. When babies are first born they have no proper immune system of their own - they have to build one. But whilst they do so they are protected 'passively' by antibodies they pick up from their mothers. IgG class antibodies are actively transferred across the placenta from mother to baby just before the time of delivery. The mother also pumps out antibodies in her first breast milk - colostrum - which the baby can pick up from the gut and use.

These antibodies are proteins made by the mother in response to the pathogens that she has encountered. Since the baby will be living in the same environment as the mother they are a good form of protection whilst the newborn's immature immune system prepares to stand on its own two feet. These antibodies are gone after about a year of life.

What you do inherit from your parents are the genes which are involved in 'presenting' things to the immune system. When you encounter a foreign protein - from whatever source - it is chewed up by antigen presenting cells and chunks of it are displayed on the surface of the cell, in a metaphorical 'cellular shop window' for other immune cells to have a look at. Depending upon the structure of the shop window, immune cells can react differently - sometimes they are fooled into thinking that what's on show is something else (to continue the analogy, imagine that the lighting in some shop windows is a bit dim). So that's why some genes you inherit from parents can give you a predisposition to an autoimmune disease - because the shop windows the encode are dimly lit and some things displayed in those windows can look misleadingly like others...

If this is the case the immune cells can get excited and attempt a ram raid to buy up what they have been fooled into thinking is on sale when it isn't. If what they target turns out to be a healthy part of the body (which is also displayed in cell shop windows) then the healthy tissue gets taken out and you have an autoimmune disease like rheumatoid arthritis, or diabetes. In both cases viruses can fool the body into turning on itself.

Chris

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx

[neilep]

quote: originally by moosehole

What I meant to say is that if someone is allergic to sperm, then this allergy has a less likely chance of being propogated to the next generation (this person may not have kids).  Not having kids is a way for things that shouldn't be passed on to not pass on.

Thanks chum....I understand now

'Men are the same as women...just inside out !'

[DrN (OP)]

so the best answer so far is allergy to sperm. my problem with this as an answer to my question is that surely an allergy would produce an allergic response, hence the couple would probably find out what the problem was soon enough. The cases I've heard of have no problems, other than not being able to conceive! so nothing medically diagnosable.

if you're allergic to sperm I suppose you'd still be able to go through IVF, so still have kids and still pass the allergy on! you could say that IVF and other methods are interfering with natural selection.

[MooseHole]

As Chris said, only the predisposition for the allergy would be passed on.  And from what fishytails said, it would only be a predisposition for an allergy to some particular set of sperm.

[jai]

surely it could also be to do with stress and phsychology. it does seem that the body is quite responsive to what a person believes and if a couple are having trouble conceiving and this becomes a big problem, leads to more stress, less chance of conception, more trying and stress, less love, less chance of conception...... you see where i am going. this could go on for years! then imagine the relief when you are with another partner and all of a sudden you are not worried about whether you can get pregnant (because you either secretly believed it was the old partners fault or you have now given up on the idea because you believe it was your fault) then WHAM, no stress, lots of fun and you're pregnant!


yaaaaay!!!!!!!

[charmedby4]

You might want to get tested for Ureaplasma.

[Rehanaci]

You may get a blood test or female fertility test to check your levels of follicle-stimulating hormone, or female fertility test, which activate your ovaries to prepare an egg for release each month. High FSH can mean lower fertility in women.      

aci-diagnostics dot com