twins

[coffee]

i am so confused
can any one explain for me that how can a mother be pregnant with twins boy and girl at the same time
even she has everthing identical the same diet and number of attamps and suppliments
does she produce two eggs at different time but i read here the time does not sway
second question if a women has twins from one divided egg can they be only girls or boys not to be mixed (girl and boy)

sorry for my bad English

[atomic sagebrush]

Because swaying isn't 100%, at best it's somewhere between 2/3-3/4 successful depending on the sway tactics used. Plus, most people don't really sway anyway and are doing a variety of things that may sway a little pinker or a little bluer and it just works out that way that both X and Y sperm are able to make it through. Imagine if a lady is losing weight but taking a prenatal, how would that sway? Imagine if she was vegetarian but she ate high calories, how would that sway? In every conception, some X and some Y sperm can get through, and then X finds one egg and Y another. Interestingly, there are fewer BG twins than there "should" be according to statistics; this may be down to things that are swaying, or it may be because twin pregnancies seem to be harder on boys than on girls, or a combination of the two.

Women who have twins DO NOT make eggs at different times. That is a myth that has been completely debunked, though some of the sites that promote Shettles timing still say that (because it helps them promote Shettles timing, also completely debunked). Most twins, if not ALL of them, come from eggs that are released very close together, separated at most by a few hours. After the first egg is released, the hole the egg comes out of, called the corpus luteum, makes a lot of progesterone that stops other eggs from being released. So unless the second egg is released fairly soon, it can't be ovulated any more due to that progesterone the corpus luteum makes. It's just impossible that more eggs are released many days later. I know there are some claims to that effect, but they are not true (even if they are made by doctors or are popularized in the media) and are a result of a phenomenon where one twin grows more slowly than another twin, and does not develop as well, so one twin looks younger at birth than it really is.

If an egg splits into two after fertilization, then the babies are identical twins and will both be boys or both be girls. Very, very, very rarely, there is a case where one of the twins has an abnormality that affects their sex (so, the Y chromosome in one twin doesn't work right) and so it ~looks~ like one is a boy and one is a girl or vice versa, but at the time the egg divided, they were genetically either boys or girls. The egg cannot split till after fertilization and it's fertilization that determines sex, so identical twins by definition are the same sex (even if something goes wrong after that point that makes them LOOK like they're different sexes, they aren't on the genetic level)

[coffee]

ok i see
do you mean in twins condition the two eggs come from one ovary
i was thinking ever ovary produces an egg

[atomic sagebrush]

There are two kinds of twins. One of them are fraternal, where two different eggs are released. These eggs can come from both ovaries, but one ovary can also release more than one egg. Your ovaries actually develop many eggs every month, 15-30, but only the 1-2 best eggs are released. (this is how IVF works - doctors can cause many of those eggs to reach maturity and then remove them surgically from the ovaries) So in the case of twins, you can have one egg from each ovary, or two from one and zero from the other.

Then once you have happened to release two eggs, they are both fertilized and successfully implant in the uterus, and fraternal twins are born. They don't look just alike, and can be BG, GG, or BB.

But then there are also identical twins. In identical twins, you have one egg, that is fertilized, and then something happens. the fertilized egg, which is ALREADY XX or XY, then splits into two, and both balls of cells continue to divide. You have two babies develop, which are genetically identical - either both boys or both girls.