Twelve Weeks

http://parenting.ivillage.com/pregnancy/0,,nc26-10,00.html

Your baby-to-be is now 60 to 65 millimeters long or about two and a half inches long, and weighs about 14 grams. He or she has the ability to swallow and absorb and discharge fluids. Hands, now complete, are growing fingernails. Even tooth buds are appearing. Your baby's face now has a distinctly human appearance.

http://www.pregnancy-info.net/babydevelopment_12.html
Now that you are 12 weeks pregnant, your baby already weighs 14 grams, has reflexes and because of muscular development, can even move its limbs! You would now be able to hear your baby's heart beat with the aid of a Doppler, which your practitioner should have. Your baby's heart rate will be very fast, at about 160 beats per minute.
You'll also now notice a face profile, complete with a tiny chin and nose. The baby is now able to swallow, and its tiny fingernails and toenails are forming.

http://www.babiesonline.com/pregnancy/week-by-week/week12.asp
By now, nearly all of your baby's organs, structures and systems are fully formed. The heart begins pumping several quarts of blood through your baby's body every day. Your baby has also begun to develop nerves and a spinal cord, allowing him to feel some types of pain. While your baby's brain is not the same size it will be at birth, it does have the same structure. Fingers and toes have separated and hair and nails continue to grow. Your baby is approximately 2.5 - 3.5 inches and weighs about 12 - 14 grams.
Also, the external genitals can now show definite signs of male and female gender. Before, Where there was only reflex movement, your baby now moves spontaneously and at random, although his movements are still too slight to be felt. With the use of a Doppler, you may be able to hear your baby's heart beat at this office visit. It will sound very fast, similar to the sound of a running horse’s hooves. Once you hear this sound, you can rest assured that your risk of miscarriage is greatly reduced.

http://pregnancy.baby-gaga.com/calendar/week12
Even though your little Einstein’s body is still growing quite rapidly 2 inches long right now, the overall super-speedy growth of their amazing brain continues to leave the head proportionately larger than the body— and is actually slightly more than one third of their total body mass! The head and neck are still straightening at this point as can be seen by their little chin lifting off of the chest. Your baby is also actively rehearsing “breathing” by using amniotic fluid to prepare the lungs for future air respiration.
The big news: your little pooper is now officially going to need diapers! Although a majority of the waste produced is transferred to the mother’s system for discharge (to avoid having it linger in the amniotic sac), some urine is released to the amniotic fluid and your baby will actually breathe it in before it passing it on to your for discharge. Not to worry, urine--in this particular form, is completely harmless to your baby.