Your baby's gender is determined by specific chromosomes. The tube-like structures that contain her unique genetic blueprint.
Healthy human beings have 23 chromosome pairs: one chromosome in each pair is inherited from each parent. The 23rd pair of chromosomes is called the sex chromosome and it determines what sex a baby will be.
A woman's egg always contains the female chromosome, known as X and a man's sperm contains either an X (female) or Y (male) chromosome. An embryo that has two X chromosomes will be female, whereas one with an XY combination will be male.
It is therefore the man's sperm that determines whether a baby is male or female.
For a less scientific way to find out, here are some of the fun way to predict whether you are carrying a boy or a girl.
Fetal Heart Rate The next time your doctor listens to your baby's heartbeat, ask for specifics. Allegedly, if the fetal heart rate is more than 140 beats per minute, it's a girl; less than 140 beats per minute, a boy.
Morning Sickness Somewhere along the way, people began to assume that if you suffered through bouts of nausea in your first trimester, you were more likely to have a girl than if you had an easy, vomit-free pregnancy.
Your Grocery List If you're craving ice cream, you're having a girl. Pickles? A boy. Because girls are stereotypically "sugar and spice and everything nice," legend has it that eating sweets means you're having one, but opting for savory, salty dishes is a sign you've got a boy baking.
Your Bump You can apparently tell a lot by the way you carry your baby bump. If you're carrying high and on the sides, it's allegedly bound to be a girl. If you're carrying low or if it looks to be a perfectly round, ball-like bump, it's most certainly a boy.
The Key Test Although it's hard to accurately test this on yourself once you know the outcomes, the idea is that you set a key in front of you, and if you pick it up by its top — the wide, rounded part — you're going to have a girl. If you naturally pick it up by the narrow end, it's a boy.
The Pee Test Your days of inspecting your urine aren't over yet! Some say the color of your pee can be an indicator of your baby's sex, with bright yellow urine for a boy and dull yellow urine for a girl.
Acne Alert It's by far the cruelest trick, especially if someone calls you out on it, but if you're breaking out in zits or aren't really exhibiting that gorgeous pregnancy glow, you might be able to blame it on an eventual daughter. According to legend, girls steal their mother's beauty.
Ring on a String If you're married, pop off your wedding ring and tie it to a string. Hang it over your belly, and see what happens. If it swings in a circle, you're having a boy, but if it sways back and forth, it's a girl.
Conception Equation Loosely based off an ancient Chinese gender cart, which was created more than 700 years ago before being buried in a tomb, it's as simple as basic math. If your age at the time of conception plus the number of the month in which you conceived is even, it's a boy. If it's odd, it's a girl.
How You Wake Up Sleep is a tricky subject for any pregnant woman, but one myth attests that if you always seem to wake up on your left side, it's a girl, and if you find yourself sleeping on your right side more often, it's a boy.
Palm Reading No, you don't have to go find a fortune teller — all you need to do is look down at your hands. Are they dry and cracked? Some say that means a boy is on the way. If your palms are soft and supple, you might be having a girl.
Your Cup Size No two breasts are created equal, certainly not with all the hormonal changes that come with pregnancy. To that end, a generations-old method for determining the sex of the baby is by boob size! If your left breast feels larger, it's a boy. If the right is heftier, you've got a girl.