You meet a couple. They tell you they have two children. Their oldest child is a boy. What is the probability that the second child is also a boy?
I would assume, without any other information on the couple, it's 50/50 but I'm not sure if there's a medical reason for people being more likely to produce either boys or girls.
The odds of having a girl seem decrease after having each boy, but only very slightly. Even after 3 boys, you are only 6.4% more likely to have a 4th boy than a girl."
I digress a bit .. BUT ... a good friend of my ex wife had given birth to five girls, she was really desperate to give her husband a son but was equally sick of being almost permanently pregnant .. she and her hubby ran a successful business and over the years made a nice few quid .. so .. if at first (or five times) you don't succeed, try again at the age of (about) 43 after a failure to conceive naturally, she paid for IVF treatment in a last attempt to birth a son .. IVF was so successful that she became pregnant with quads, no messing there, not twins, not triplets, 'kin quads .. birth time .. out they came .. number 1 .. a girl .. number 2 .... a girl ... number 3 ... a girl .. desperate times .. number 4 ? .. go on guess
boy !!!! .. so eight girls and one lil boy ((:>) .. and she insisted it was all worth it .. one of those 'you could NOT make it up' stories
I digress a bit .. BUT ... a good friend of my ex wife had given birth to five girls, she was really desperate to give her husband a son but was equally sick of being almost permanently pregnant .. she and her hubby ran a successful business and over the years made a nice few quid .. so .. if at first (or five times) you don't succeed, try again at the age of (about) 43 after a failure to conceive naturally, she paid for IVF treatment in a last attempt to birth a son .. IVF was so successful that she became pregnant with quads, no messing there, not twins, not triplets, 'kin quads .. birth time .. out they came .. number 1 .. a girl .. number 2 .... a girl ... number 3 ... a girl .. desperate times .. number 4 ? .. go on guess
boy !!!! .. so eight girls and one lil boy ((:>) .. and she insisted it was all worth it .. one of those 'you could NOT make it up' stories
I digress a bit .. BUT ... a good friend of my ex wife had given birth to five girls, she was really desperate to give her husband a son but was equally sick of being almost permanently pregnant .. she and her hubby ran a successful business and over the years made a nice few quid .. so .. if at first (or five times) you don't succeed, try again at the age of (about) 43 after a failure to conceive naturally, she paid for IVF treatment in a last attempt to birth a son .. IVF was so successful that she became pregnant with quads, no messing there, not twins, not triplets, 'kin quads .. birth time .. out they came .. number 1 .. a girl .. number 2 .... a girl ... number 3 ... a girl .. desperate times .. number 4 ? .. go on guess
boy !!!! .. so eight girls and one lil boy ((:>) .. and she insisted it was all worth it .. one of those 'you could NOT make it up' stories
You meet a couple. They tell you they have two children. Their oldest child is a boy. What is the probability that the second child is also a boy?
I would assume, without any other information on the couple, it's 50/50 but I'm not sure if there's a medical reason for people being more likely to produce either boys or girls.
Yes, a lot of people would assume that. As did I until I heard the answer.
Cant remember which way round it is but one sex sperm swims faster than the other but has a shorter life span.
Therefore if the couple had "relations" at the time of ovulation it is likelier to have sex 1. The further back you go before ovulation increases the chances of the baby being sex 2.
Cant remember which way round it is but one sex sperm swims faster than the other but has a shorter life span.
Therefore if the couple had "relations" at the time of ovulation it is likelier to have sex 1. The further back you go before ovulation increases the chances of the baby being sex 2.
Science.
It must be the boy sperm that lives longer as I'm shit at swimming.
Probably total bollox so don't take it as gospel and Not clicking on the link so no idea what they say but, going by an 'old wives tale' if the first was a boy then I suspect the next one will also be a boy. Doesn't producing girls need something a little extra from the male donors sperm so, if that is the case, then if that something extra wasn't present when the first child was conceived then chances are it's not going to be there when producing subsequent children.
A relation of mine had a daughter as a first born who sadly past away shortly after birth. She went on to have a son next but was also desperate to have another girl. Gave up after 4 boys, all single births.
If they had two boys they'd have said 'two boys' not two children. 100% a girl
I like that answer. Of all the wrong ones so far, it's the most interesting.
Depends on how you know that the eldest is a boy. If they told you, then Leuth is likely right. But if you found out another way, then that's not an indicator and has no bearing on the likelihood either way.
This isn't the Monty Hall problem as far as I can tell
No it isn't the Monty Hall problem - similar logic but different probability theory - Monty Hall is based on a second event having no bearing on the first event's probability.
As the previous fertilisation has no relationship to the principal of probability, the chances of the second and subsequent children being male are still 1:1 or 50:50.
Meiosis in males produces an equal ratio of gametes containing the x or Y chromosome. The female gamete has always got the X chromosome. On ejaculation therefore an equal proportion of male x and Y chromosomes are released. Therefore the chances of a male being conceived is always 1:1.
Comments
http://www.ingender.com/gender-info/odds-of-having-another-boy-or-girl.aspx
"Odds of Having a Girl After 1, 2, or 3 Boys
The odds of having a girl seem decrease after having each boy, but only very slightly. Even after 3 boys, you are only 6.4% more likely to have a 4th boy than a girl."
When I was little, I used to think boys came from one bollock and girls from the other. I was never very good at science.
at the age of (about) 43 after a failure to conceive naturally, she paid for IVF treatment in a last attempt to birth a son ..
IVF was so successful that she became pregnant with quads, no messing there, not twins, not triplets, 'kin quads .. birth time .. out they came .. number 1 .. a girl .. number 2 .... a girl ... number 3 ... a girl .. desperate times .. number 4 ? .. go on guess
boy !!!! .. so eight girls and one lil boy ((:>) .. and she insisted it was all worth it .. one of those 'you could NOT make it up' stories
not even a thought in her head about that ..
Therefore if the couple had "relations" at the time of ovulation it is likelier to have sex 1. The further back you go before ovulation increases the chances of the baby being sex 2.
Science.
If so, it's a 1/3.
The answer is 1/3 or 33.333% change of being a boy - that's the only correct answer (although I like the thinking of some posters!)
Other than that 50%