These are not abortion pictures so I assume they are permissible. I believe comparison to Holocaust is appropriate.
Conception
Step one of conception is when the sperm penetrates the egg to complete the genetic make-up of a human fetus. At this moment (conception), the sex and genetic make-up of the fetus begins. About three days later, the fertilized egg cell divides rapidly and then passes through the Fallopian tube into the uterus, where it attaches to the uterine wall. The attachment site provides nourishment to the rapidly developing fetus and becomes the placenta.
Baby's Development at 4 Weeks
After 4 weeks, the basic structures of the fetus have begun to develop into separate areas that will form the head, chest, abdomen, and the organs that are contained within them. Small buds on the surface will become arms and legs. A home pregnancy test should be positive at this stage of development (most tests claim positive results one week after a missed period).
Baby's Development at 8 Weeks
At 8 weeks, the fetus is about one-half an inch long (1.1cm). Facial features such as developing ears, eyelids, and nose tip are present. The limb buds are now clearly arms and legs, while the fingers and toes are still developing.
Baby’s Development at 12 Weeks
At 12 weeks, the fetus has grown to about 2 inches (4.4cm) in length and may begin to move by itself. The fingers and toes are discernible and the fetal heartbeat may be audible by Doppler ultrasound. The developing sex organs may be identified by ultrasound techniques.
Baby's Development at 16 Weeks
At 16 weeks, the fetus is about 4 and one-half inches long and resembles an infant; the eyes blink, the heartbeat is easier to locate, facial features (nose, mouth, chin and ears) are distinct, and the fingers and toes are clearly developed; the skin on the fingers and toes even have distinct patterns (fingerprints!). Women should be able to feel the uterus at about 3 inches (6.6 cm) below the belly button; this is the beginning of the "baby bump" (abdominal swelling due to an expanding uterus) in some women.
Baby's Development at 20 Weeks
At twenty weeks, the developing baby is about 6 inches long (13.2 cm) and may weigh about 10 ounces. The baby may begin to make movements that the mother can feel at about 19 to 21 weeks; this baby movement is termed "quickening". The baby at this stage of development can move its facial muscles, yawn, and suck its thumb. The expanding uterus at 20 weeks is felt at the level of the belly button.
It's Time for an Ultrasound
In the US, women that have prenatal care usually have an ultrasound done at 20 weeks to determine that the placenta is attached normally and that the baby is developing without any problems. The baby’s movements can be seen with Doppler imaging, and usually the sex of the baby can be determined at this time, so if you want to be surprised about the sex of your baby at delivery, let your doctor know before the Doppler ultrasound is started!
Shown here is a 2D ultrasound (inset) contrasted with a 4D ultrasound, both at 20 weeks.
Baby's Development at 24 Weeks
At 24 weeks, the baby may weigh 1.4 pounds and can respond to sounds. Doppler studies show the sound response by measuring movement and heartbeat rates. Sometimes the baby will develop hiccups that the mother can feel! The baby's inner ear canals are developed at 24 weeks, so researchers speculate the baby can sense its position in the uterus.
Baby's Development at 28 Weeks
At 28 weeks, the baby normally weighs about 2 and one-half pounds and has developed to the point that if the baby is birthed prematurely for any reason, the chances are good that the infant will survive, but usually would require a hospital stay. Your doctor may discuss signs of premature labor and suggest you (and your partner) take classes on what to do at the time of delivery of your full-term baby.