How come some people can only conceive all boys or all girls.?

Question

Because my friend has been trying to have a boy for years but it never happenen now she is stuck with nine girls and no they do not have the same father does it mean they can not make kids of the opposite sex is it scientific reason or a family history reason i mean what is it.

Answer 1

I have heard that if a woman has had several girls (3 or more) she is more likely to have another girl than to have boy. I do not know the scientific explanation but it could be related to when she has sex.

Male sperm (those carrying the Y chromosome) are supposed to swim faster than female (those carrying X) because the X chromosome is much larger and therefore much heavier than the Y. Female sperm are speculated to live longer then the male. Supposedly if you have sex a couple of days before the women ovulates the child is more likely to be female. If you have sex right after ovulation the child is more likely to be male.

I do not know if this explains her situation and I do not think it is scientifically proven but it could be a possible explanation.

Answer 2

There are countless variables and confounders to this; and biologists are learning this more and more even as we speak. For as soon as one paper is published, another is presented to supplant the preceding one.

It is known that both genetic propensity and environmental influence play key roles, which in actuality are one and the same, for these are inexorably tied: one is ever depending upon the other... For nothing ensues in a void, whether animate or inanimate.

Answer 3

With my knowledge in molecular biology and genetics and illumination of sayings of one of the prophet: I think some women are powerful women, some men are powerful men, they favor their sex. Powerful man produces semen (fluid containing sperm which is ejaculated by males) favoring fusion of sperm having Y chromosome, while powerful women produce fluid together with egg favoring fertilization with sperm having Y chromosome.
who powerful between man or woman is favoring its sex in their children.

There might be some clues in their genetic make up, in you question, it has to be a genetic combination making this lady a powerful lady. It is need to be investigated.

Moreover, this phenomena is also related with the physiology of sperms, there should be -at least slightly- some difference between sperm having X chromes and Y.

Answer 4

this is a myth, i'm not sure if it's true but so far it's been accurate. you look at the crease of the male's forehead.. from the bottom(closer to the eyebrows) to the top. If the crease is broken like this: ___ ____ then it's a girl. if the crease is not broken ie: _____ then it's a boy....