Family gathering puzzle

[MrsLizzy]

I found this puzzle in a book and can't work it out.   The question is:

How can a family gathering of seven people contain:

two mothers
two fathers
one grandmother
three grandchildren
two sons
one brother
two sisters
one father in law
one mother in law
one daughter in law
four children

Can anyone solve it please?

[Nadine Moore]

Mrs Lizzy

Does this make sense:

Father/Father in Law married Mother/Mother in Law/Grandmother   

They had children as follows:

Sister/Child
Sister/Child
Brother/Son/Father/Child married Mother/Daughter in Law

They had one child:

Son   
Child   

That's my best guess

Nadine

[Richard Knott]

I think that hits all the targets except the 3 grandchildren.
Try: a man, together with his parents, his wife, and their three children (two daughters and a son)

[Nadine Moore]

rj

Thats how i meant to write it but I completely missed the grandchildren

Father/Father in Law married Mother/Mother in Law/Grandmother   

They had a child as follows:

Brother/Son/Father/Child married Mother/Daughter in Law

They had children as follows:

Sister/Child/Grandchild
Sister/Child/Grandchild
Son/Child/Grandchild

Nadine

[Kevwood]

think the brother is the last one nadine rather than the only child 

Kev.

[Nadine Moore]

Kev
That must be why my own tree is in a mess 

Is this better..........

Father/Father in Law married Mother/Mother in Law/Grandmother

They had a child as follows:

Son/Father/Child married Mother/Daughter in Law

They had children as follows:

Sister/Child/Grandchild
Sister/Child/Grandchild
Brother/Son/Child/Grandchild

Just one question, why are there no daughters or grandfather in Mrs Lizzy's original list?

Nadine

[Jones the Search]

I don't think it's a puzzle 
Just a submitted entry on the IGI 
     Patricia 

[MrsLizzy]

Just one question, why are there no daughters or grandfather in Mrs Lizzy's original list?

Nadine

That's what had me puzzled.  No grandfather, therefore he can't have been among those present at the family gathering. 

[Chasing-fireflies]

It seems to be the same as the riddle:
Brothers and sisters have i none but this mans father is my fathers son, who am i?

The answer to this one is his son, generations!  This is just generations too. I have heard many riddles like this and it usually turns out to be the same.Start with the youngest generation.