This is week for of the pregnancy. Chris’ heart started beating 18 days after conception. Chris may have a different blood type than him mom’s. (We know that he is a different sex.) Chris’ neural tubes are forming and will develop into the nervous system. Already, Chris has the foundation for thought, senses, feeling, and more. The amniotic sac, which will house Chris, is formed and the amniotic fluid will cushion Chris throughout pregnancy. Chris now has a yolk sac which supplies blood and nutrients until the placenta has developed and is ready to take over.