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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Original poster

Blood Groups

89 replies

DiscoLightsOnAFridayNight · 13/01/2022 15:27

I’m not married but will use the in law abbreviations for ease.

I went to a family dinner at my PIL’s house on Saturday and FIL was playing ‘Supermarkets’ with the kids there and he used his blood donor card as a pretend credit card; I noticed that his blood group is A. Now a few years ago MIL and SIL donated blood at a drive I was volunteering at and I know for a fact that they are both blood group A as well. The thing is, my DP is AB.

I did some googling and know there can be rare variations in blood type when the O blood group is involved (either the parents or the resulting children) but as far as I can see random B’s can’t just pop up without a biological parent carrying it, is that right? I didn’t do too well in biology so I’m hoping some of you lovely people can give me a definitive answer either way as I can’t help but jump to conclusions here.

(I left out the +/- as I don’t think they make a difference but can add them if they do).

If the situation is as I suspect though, should I tell DP? There’s a whole complicated backstory involved and I don’t want to cause any trouble but at the same time, I would want to know if it was me and DP is very much that type of person too.

YABU - Leave well enough alone and keep your trap shut.

YANBU - Speak to DP about if it if there isn’t a simple explanation.

Thank you!

OP posts:
Getyourjinglebellsinarow · 13/01/2022 15:31

Nope random Bs don't pop up. Are you sure his dad wasn't using his mums donor card which would rightfully say A and his dad is actually B or AB.

AB children don't come from AA AA parents. I would never ever open this can of worms though if DH is happy with his parents and childhood

TyrannosaurusRegina · 13/01/2022 15:42

@Getyourjinglebellsinarow

Nope random Bs don't pop up. Are you sure his dad wasn't using his mums donor card which would rightfully say A and his dad is actually B or AB.

AB children don't come from AA AA parents. I would never ever open this can of worms though if DH is happy with his parents and childhood

Can an AB arise from a B grandparent?
Clarissa76 · 13/01/2022 15:58

No, AB cannot arise from a B grandparent.

I wouldn't say anything. It's possible that it was your MIL's card or that the wrong thing had been written on the card or you misread it, misremember etc. I also think that, if you learned MIL's blood group while volunteering, you need to treat it as confidential.

GeorgieTheGorgeousGoat · 13/01/2022 16:02

There's also a possibility that your recollection of mil's blood group is incorrect.

WhiteXmas21 · 13/01/2022 16:05

What Clarissa said. You know your MIL blood group as a volunteer at a blood drive. That is confidential information.

You may not be in the UK, but if you are, using that info now would be considered a serious breech of GDPR.
Plus it’s a shitty thing to do to your partner and his family.

Pedalpushers · 13/01/2022 16:06

In these cases it is usually more likely that someone has the wrong blood type, blood typing isn't infallible.

Original poster
DiscoLightsOnAFridayNight · 13/01/2022 16:12

Thanks @Getyourjinglebellsinarow and yes I’m definitely sure as I was the ‘cashier’ at one point so handled the card, it was definitely FIL’s card and his blood group was definitely A.

DP loves his father to bits but he wouldn’t say his childhood was happy as he’s always had a contentious relationship with MIL to the extent that he’s had counselling in adulthood to try and make peace with it. There’s a whole backstory involving DP and MIL which is probably clouding my judgement on this to be honest and sending my imagination into overdrive.

OP posts:
chesirecat99 · 13/01/2022 16:26

It's not impossible:

www.independent.co.uk/news/science/human-chimera-man-fails-paternity-test-because-genes-in-his-saliva-are-different-to-those-in-sperm-a6707466.html

Although... Occam's razor, the simplest explanation is usually the correct one...

LostMyLastHatfulOfWords · 13/01/2022 16:27

There are some things no-one wants to know. His parents clearly don't think he would be better for having this information. What if your MIL (who has a contentious relationship with her son) had him after rape?

You don't know for sure that your DP would prefer to have that sort of knowledge.

In any case, this is information you shouldn't have... so should probably be held in confidence by you.

I say this though understand that it is very difficult (painful even) to keep secrets from a DP.

Original poster
DiscoLightsOnAFridayNight · 13/01/2022 16:29

@WhiteXmas21

What Clarissa said. You know your MIL blood group as a volunteer at a blood drive. That is confidential information.

You may not be in the UK, but if you are, using that info now would be considered a serious breech of GDPR.
Plus it’s a shitty thing to do to your partner and his family.

As Clarissa76 and GeorgieTheGorgeousGoat said, I thought I might be mistaken so I asked MIL if she remembered her blood group on Saturday and she said it was type A as I originally thought so surely I’m not breaching GDPR as she told me in a social conversation? I also didn’t say “is your blood group A” therefore using confidential information learned in my capacity as a volunteer, I only asked her if she remembered her group and she voluntarily told me it was A.

As for it being a shitty thing to do, believe me if DP was completely happy and had a happy childhood then of course I would keep my mouth shut and let things lie but like I said, there’s a backstory to this and it’s difficult watching someone you love struggle and look for answers when you might have information that could shed some light on the situation. Believe me I am taking no joy in this and am only trying to do the right thing for my DP.

OP posts:
CharlotteRose90 · 13/01/2022 16:36

You can’t say anything but if they are both blood type A then dp isn’t the dads sadly. That’s bloody awful secret to hide though.

TheVolturi · 13/01/2022 16:37

How do people know their blood type?

gogohm · 13/01/2022 16:42

Just leave it. There's a possibility that mil was told the wrong blood group, there's the possibility that fil was told the wrong blood group, there's the possibility that dp was told the wrong blood group, there's the possibility that dp isn't fil's because he's infertile and they had an "arrangement" with someone, there's the possibility that you mil was abandoned by Dp's father and fil brought him up as his own and finally there's the possibility that mil had an affair. Don't open a can of worms

SallyGoLucky · 13/01/2022 16:43

I think asking MIL if she remembered her blood type, hoping she would volunteer it to prove you right is quite a sneaky move tbh, and could be seen as quite calculated.

I wouldn't say anything. The trauma it would cause just would not be worth it in my opinion.

TyrannosaurusRegina · 13/01/2022 16:45

@TheVolturi

How do people know their blood type?
Because they're blood donors, you find out when you donate blood and it's on the card.
Mamamamasaurus · 13/01/2022 16:46

@TheVolturi

How do people know their blood type?
By donating - you're sent a card and a keyring with your blood group on
kitcat15 · 13/01/2022 16:46

Why would you want to be a shit stirrer?🙄

kitcat15 · 13/01/2022 16:47

@TheVolturi

How do people know their blood type?
It forms part of your maternity records if you have been pregnant
InTropicalTrumpsLand · 13/01/2022 16:47

@TheVolturi in my country it is tested at birth, and before a surgery is done in case blood bags are needed. You also learn if you donate blood.

OP, is your DP sure about his blood type? I ask because I grew up being told by my parents I was A+, like my father, until I did a surgery procedure in my 20s and it was tested, where I promptly learned I was O+, like my mother.

Otherwise, yes. I'm a biologist, and B + B can't make AB.

RedWingBoots · 13/01/2022 16:50

OP unless your DP comes to you and says I don't think my father is my father keep your mouth tightly shut.

You will open a can of worms that will have negative implications for your own children.

ProfessorSlocombe · 13/01/2022 16:55

so surely I’m not breaching GDPR as she told me in a social conversation?

except you only had that social conversation as a result of information gained under the protection of GDPR. It doesn't work that way.

DamnitImTired · 13/01/2022 16:55

OP I have a ‘potentially’ similar story but I’m just leaving it as I’m sure it will sort itself out on its own.

My DH is OP and his exw is OP which I’m sure of as she left behind all their medical records in storage which my husband ‘got’ in the divorce.
All medical records of all 3 children show blood types except for the eldest child who was conceived on a one night stand leading to Shia birth and their subsequent marriage.
Not just his birth records is the blood type missing but all his sports indemnities and school records as well.
If I had to find out that his blood type was incompatible with my DH being his father I would say something only because it’s something he questions himself.

DamnitImTired · 13/01/2022 16:56

Ps I’m not in the UK

Original poster
DiscoLightsOnAFridayNight · 13/01/2022 16:59

I think asking MIL if she remembered her blood type, hoping she would volunteer it to prove you right is quite a sneaky move tbh, and could be seen as quite calculated.

Of course it was calculated but I was actually hoping she would confirm I was WRONG and that I really had misremembered! To be honest in hindsight, I should have just kept my mouth shut then and told myself in my head that I’m wrong / she’s probably AB and forgotten it because now Im stuck in a situation where I either cause all sorts of shit or have to lie to my DP forever more even though I can see he’s struggling with certain things.

Also from a purely selfish point of view, the messenger always gets shot, don’t they?

OP posts:
ArnoldBee · 13/01/2022 17:07

Bizarrely I had this situation after going to Blood Donors. I was 17 and I was very upset. It was pre-internet so my poor Dad spent the whole day ringing round people to try and understand to console his poor daughter. It turns out genetic inheritance is not as simple as we are taught at school.

The only true way to answer this is of course an ancestry dna test...