Litter of pups all the same sex?

[Lone Pine Beagles]

I read an article where breeders of German Shepherds logged what day in the cycle their bitches were bred.
They also logged the sex of the pups.
This study was performed for several years with over a hundred breeders participating.

They determined that bitches bred on the 12th day or after had a higher percentage of female pups.
Bitches bred as soon as they'd "stand" had a higher percentage of male pups.

How can this happen if the male's Y chromosome determines sex?

It appears that the female produces more hormones later in her cycle.
I also remember that a protein is produced later on that sways the sex determination to more female.

I tried it a few years ago, waited and bred when she would barely accept the male.
Had 7 females out of 7.

Tried it again this year... she's due Tuesday!

[shawnfrazier]

It is not a wives tale the chromosomes for males is the early part in the cycle a late breeding has better chances of females the same is true with people it's science