I found this which does support JeanieK's post.
The sex of your baby is established at the moment of Conception. Dad's sperm chromosome compliment determines sex of baby. It is dependant on whether a "Y" chromosome containing sperm fertilizes the egg or an "X" chromosome containing sperm fertilizes the egg. Mom only has one type of egg - one with an "X" chromosome. If a baby has 2 "X" chromosomes, it's a girl. An XY chromosome pair is a boy.
The XX sperm ( female) tend to 'swim' slower, but live longer. The XY sperm (male), 'swim' faster, but die sooner. That is why it is said, if a woman is trying for a girl baby, to have sex a few days before her fertile day, that way when her fertile day comes, all the male sperm would have died off, leaving only the female sperm. If try for a boy, it is recommened to have sex only on the fertile day.
Some studs seem to know intuitively the ovulation timing so I guess those studs would most likely produce males. One that is not so intuitive may breed before actual ovulation, thereby producing more girls. I guess you could influence the sex to some degree through ovulation testing and controlling the fertilization process by artificial insemination. |