Fraternal Twins?

I read that 50% of fraternal twins are boy/girl. Does anyone know if this is true?

 

I have never heard that...

 

I have never heard that but i believe its for like 1/3. My twins are b/g. You should have a poll of frat twins

 

Yes it is basic statistics. Each baby has a 50% chance of being a boy or girl. Therefore there is a 25% chance of 2 boys, 25% chance of 2 girls and 50% of boy/girl.

 

QUOTE(Fletchie @ Jan 30 2008, 09:28 PM) [snapback]598020[/snapback]
Yes it is basic statistics. Each baby has a 50% chance of being a boy or girl. Therefore there is a 25% chance of 2 boys, 25% chance of 2 girls and 50% of boy/girl.


Yup, this is what I was going to say! :good:

 

QUOTE(Fletchie @ Jan 30 2008, 06:28 PM) [snapback]598020[/snapback]
Yes it is basic statistics. Each baby has a 50% chance of being a boy or girl. Therefore there is a 25% chance of 2 boys, 25% chance of 2 girls and 50% of boy/girl.

%
Why wouldn't it be a 33% chance of Boy/Boy, 33% chance of Girl/Girl, or a 33% chance of Boy/Girl??

 

QUOTE(TwinLove @ Jan 30 2008, 09:29 PM) [snapback]598023[/snapback]
Yup, this is what I was going to say! :good:



I don't know if there are real statistics to back it up, but my mathematical mind understands what the other post said.

Each baby has a 50% chance of being a B or a G.

..... B ........... G
B BB 25% GB 25%
G BG 25% GG 25%

Above equals BB 25%, GB + BG 50%, GG 25%

Not sure if the above "chart" will come out... but its the same way you'd figure out the chance of (B) blue eyes vs. (B) brown eyes from back in biology...

 

QUOTE(maybell @ Jan 30 2008, 06:55 PM) [snapback]598080[/snapback]
I don't know if there are real statistics to back it up, but my mathematical mind understands what the other post said.

Each baby has a 50% chance of being a B or a G.

..... B ........... G
B BB 25% GB 25%
G BG 25% GG 25%

Above equals BB 25%, GB + BG 50%, GG 25%

Not sure if the above "chart" will come out... but its the same way you'd figure out the chance of (B) blue eyes vs. (B) brown eyes from back in biology...

Thanks, that makes sense. My sleep deprived brain isn't what it used to be...

 

Maybel, you explained it well. Thanks!

 

QUOTE(Kyrstyn @ Jan 30 2008, 07:30 PM) [snapback]598026[/snapback]
%
Why wouldn't it be a 33% chance of Boy/Boy, 33% chance of Girl/Girl, or a 33% chance of Boy/Girl??

Because there are 4 "kinds" of fraternal twins. 25% are B/B, 25% are G/G, 25% are B/G and 25% are G/B. B/G and G/B are the same thing so there is a 50% chance, and a 25% chance for B/B and G/G each.

 

I read somewhere that boy/girl most common with fraternals followed by girl/girl and boy/boy - with identicals girl/girl more common than boy/boy

 

I've also read research saying that slightly more girls are born than boys because male fetuses are more fragile.

 

QUOTE(Jocasta @ Jan 31 2008, 04:04 AM) [snapback]598173[/snapback]
I read somewhere that boy/girl most common with fraternals followed by girl/girl and boy/boy - with identicals girl/girl more common than boy/boy


That would make sense since I've read that male babies are a little more fragile. I don't think it's a big difference though and things still work out to about 50% BG and 25% each BB and GG.

BTW, excellent explanation in a pp about there being two types of boy/girl fraternal twins (boy/girl and girl/boy) so that is why they make up 50% of fraternals.

 

From Wikipedia... The three most common variations are all fraternal: (1) male-female twins are the most common result, at about 40% of all twins born;

 

QUOTE(Fletchie @ Jan 31 2008, 02:28 AM) [snapback]598020[/snapback]
Yes it is basic statistics. Each baby has a 50% chance of being a boy or girl. Therefore there is a 25% chance of 2 boys, 25% chance of 2 girls and 50% of boy/girl.


Yep, someone actually asked everyone what their children were and the stats above were pretty accurate.

 

QUOTE(Fletchie @ Jan 30 2008, 09:28 PM) [snapback]598020[/snapback]
Yes it is basic statistics. Each baby has a 50% chance of being a boy or girl. Therefore there is a 25% chance of 2 boys, 25% chance of 2 girls and 50% of boy/girl.


Yep, this is correct.

 

I don't know abuot male fetuses being more fragile, but I do know that the male sperm swims faster and dies quicker than female sperm. So unless both eggs are fertilized at the very same time, you have a better chance of the female sperm fertilizing the second egg. I would imagine that depending on when you ovulated (this being concieving naturally... don't know about IVF) even with a second egg, a female sperm can last for days... unlike the male. Explaining why it's easier to have girls than boys and why more fraternal twins are boy/girl.