• • • • • • • • • • embryo - - - - - - - - - - - foetus (after 8-10 weeks) - - - - - - baby (after birth) - - - - >

|———————————————— embryonic stage —————————————| |———fetal stage———|

The predominance of human biological research confirms that human life begins at conception—fertilization

• as soon as the development of the embryo begins → stage 1: when a sperm fertilizes an oocyte and together they form a zygote
• Human development begins after the union of male and female gametes or germ cells during a process known as fertilization
  • fertilization: is a sequence of events that begins with the contact of a sperm with a secondary oocyte (aka. ovum) and ends with the fusion of them → the fertilized ovum is the zygote
• scientifically something very radical occurs between the processes of gametogenesis and fertilization the change from a simple part of one human being (i.e., a sperm) and a simple part of another human being (i.e., an oocyte usually referred to as an "ovum" or "egg"), which simply possess "human life", to a new, genetically unique, newly existing, individual, whole living human being

or

• as soons as you have an embryo: the developing organism from the time of fertilization until significant differentiation has occurred, when the organism becomes known as a fetus.
  • embryo: an organism in the earliest stage of development

In Vitro Fertilization

1. egg production stimulated by hormone therapy
2. eggs retrieved from ovary (= Eierstock)
3. sperm sample provided
4. eggs and sperm combined to allow fertilization
5. fertilized eggs introduced into uterus

The four stages of the development

1. zygote: week 1-2
   • ovum gets fertilized → zygote
   • 2-cell-stadium → 4-cell-stadium → 8-cell-stadium
   • morula
   • blastocyte (4 days)
   • implanted blastocyte
2. embryos: week 3-10
   • größere struktuerelle Fehlbildungen am ZNS und PNS
3. foetus: week 11-38
   • physiologische Defekte und kleinere strukturelle Fehlbildungen
4. baby: as soons as birth is given

Development of mind