I am trying to conceive a girl for my first child. I may only get one chance at a child due to medical issues... I would like that one to be a girl if I can... Or at least a healthy baby.

There is no way to have a better chance at getting a girl. Leave it to nature.

I do not understand your question if you have one.

Having a girl is pure luck. There are no foods you can eat, sexual positions you can try, or vitamins you can take that will insure you have a girl.

It is all up to which sperm inseminates the egg, either X or Y.

Yep what ever you get your hubby makes that decision and you know what you need to be thankfull for whatever you have because it's a special gift.

There is no surefire way to guarantee what sex you'll get, but as a mom of each, I have to say they are both incredible.

Ok, no guarantees but this may help increase your chances, certainly won't hurt. I've heard of this and sounds logical to me. Rather than try to explain it myself I found this on the web:

The basic premise is that men produce two types of sperm, the X (female) and Y (male). According to studies, the male (Y) sperm are smaller and weaker but faster than the female (X) sperm, which are bigger, stronger and slower. Understanding this information helps in manipulating the sex of your child.

The right time
The most important factor in gender selection is the timing of intercourse during the monthly cycle, so the woman must know her cycle (ovulation predictor kits are available at most pharmacies). The belief is that the closer to ovulation you have sex the more likely it is that you will have a boy. However, if you have sex two or three days prior to the egg being released, you have a better chance of having a girl. Basically, if you have intercourse right at or near ovulation then the Y sperm will make it to the egg quickly and you have a boy, whereas if the sperm is released two or three days before the egg, the Y sperm will die off and there will be more X sperm left waiting for the egg to appear and fertilisation will most likely result in a girl.

Vaginal pH
The pH of a woman's vagina is also very important. An acidic environment favours girls, since it will kill the weaker male sperm first and leave a greater number of X sperm to fertilise the egg. So, if you are trying for a boy, a good time for intercourse is when the vaginal balance changes to alkaline - on the day you ovulate - otherwise the male sperm will either slow down or die in an acidic environment.

Sexual position
Position of intercourse and depth of penetration are also important, partly because of pH. The closer to the entrance of the vagina, the more acidic the woman's tract is. Deep penetration places the sperm closer to the egg and gives the faster male sperm a head start.

Don't know if it will work but like I said won't hurt. Good luck!