Conception typically occurs about two weeks after your last period begins. To calculate your due date, your health care provider will count ahead 40 weeks from the start of your last period. This means your period is counted as part of your pregnancy — even though you weren't pregnant at the time.
http://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-care/art-20045302
In boys, the bud develops into the penis and starts to elongate at around 12 weeks. The outer membrane grows into the scrotal sac that will later house the testicles. By 22 weeks, the testes have formed in the abdomen. They already contain immature sperm.
http://www.babycentre.co.uk/v1027493/inside-pregnancy-girl-or-boy-video
Your baby is due and fully ready for life outside the womb. The average weight of a newborn is about 7 1/2 pounds, and the average length is about 20 inches. If you go more than one or two weeks past your due date without delivering, your doctor may decide to induce labor. Learn more:
http://www.babycenter.com/0_fetal-development-timeline_10357636.bc
Inside pregnancy: your baby takes shape (video). Inside pregnancy: your baby's DNA (video). Inside pregnancy: how your baby hears sound (video). Inside pregnancy: your baby's sight and eye colour (video). How your body changes in pregnancy: video. A 3D animated look at how girls and boys develop in the womb.
http://www.babycentre.co.uk/v1027493/inside-pregnancy-girl-or-boy-video
If they can’t tell what sex your baby is, you don’t get your money back either! 20-week standard ultrasound. Our advice is to wait until your doctor is able to schedule you for a gender determination ultrasound. This is usually the twenty week ultrasound and that is not too long to wait.
http://www.conceiveeasy.com/get-pregnant/when-will-your-doctor-know-your-babys-gender/
Sex Organs Are Visible. Although your baby's gender is determined immediately upon fertilization, you will not be able to know the sex until about the 16th to 18th week of pregnancy. At around the sixth week your baby will develop a small bud called the genital tuber at the site of the genitals. This will look the same for boys and girls until around the 9th week when the sex organs begin to form.
http://www.livestrong.com/article/231357-when-does-a-baby-develop-gender/
Fetal development three weeks after conception. The fifth week of pregnancy, or the third week after conception, marks the beginning of the embryonic period. This is when the baby's brain, spinal cord, heart and other organs begin to form. The embryo is now made of three layers.
http://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-care/art-20045302
Your baby-in-the-making is a ball of cells called a blastocyst. The blastocyst already contains a full set of DNA from you and your partner, which determines sex, eye color, and other traits. 4 weeks. The ball of cells has officially become an embryo and is about the size of a poppy seed. Over the next six weeks, all of your baby's organs will begin to develop, and some will start to function. 5 weeks. Your baby's tiny heart begins to beat – at twice the rate of yours. His entire body is only about the size of a sesame seed.
http://www.babycenter.com/0_fetal-development-timeline_10357636.bc
However, since not all babies develop the same, it can be hard to see this on an ultrasound this early. Boutique ultrasounds. If you want to wait until your doctor or ultrasound tech can clearly see your baby’s genitals, you need to wait until around 20 weeks. This is usually when most doctors recommend ultrasounds for gender determination, since the baby’s girl/boy parts should be further developed by this time.
http://www.conceiveeasy.com/get-pregnant/when-will-your-doctor-know-your-babys-gender/
Narrator: Your baby's sex is set at conception. At around 7 weeks, your baby's internal sex organs – such as ovaries and testes – begin to form in the abdomen. Male and female sex organs and genitalia look the same at this stage because they're derived from the same structures. At around 9 weeks, boys and girls begin to develop differently. In girls, a tiny bud emerges between the tissue of the legs. This bud will become the clitoris. The membrane that forms a groove below the bud separates to become the labia minora and the vaginal opening.
http://www.babycentre.co.uk/v1027493/inside-pregnancy-girl-or-boy-video
when does fetus develop gender
At around six weeks fetus develop gender.