I am here with my third theory;And yes I do think so that Ben and Gwen are Sibling.
Want to know why I think so;-
MAX TENNYSON
CARL TENNYSON FRANK TENNYSON
BEN TENNYSON GWEN TENNYSON & KEN TENNYSON
There are no arrows try to make sense of this chart.
In 1998 there was 1.2 % increase in population.OR lets say there is a city A with 1000 total population in 1997 then it would grow to 1012 people in 1998.
As Carl and Frank are only known child of Max so finding out probability of Ben and Gwen being born in same year to respective father would be;
1000/500=2 -------> which is number of Max's child
So, 1.2/500=0.0024%------> chances of being born in same year
And chances of there being born on same date are
0.0024/365=0.00000657534%
Yes i know it says that
It would take 657534000 brothers to have 1% chance of having babies on same day.
NOW FOR TWIN THEORY
Chances for twin pregnancy are 3 in 1000
Process same as above;-
1000/500=2------>Number of Max's child
3/500=0.006%
And as twins are born to single mother so we do not need to find chances of each mother.....
HENCE;;;;;; Chances of
GWEN AND BEN BEING TWIN are 1000 times more than being cousins and sharing same Birthday.
Please tell me about your thoughts in comments