TABLE 1.

Key stages, morphogenetics events and derivatives of human reproductive biology and embryo-foetal development.

Stage no	Key stages and morphogenetic events	Derivative organs and systems
1	Sex determination
2	Gametogenesis
3	Fertilization
4	Zygote formation
5	Implantation
6	Blastulation
7	Gastrulation
8	Placenta formation
9	Neurulation
10	Ectoderm formation and its derivatives	a. Central nervous system
		b. Peripheral nervous system
		c. Autonomous nervous system
		d. Integumentary system
11	Mesoderm formation and its derivatives	a. Somitogenesis
		b. Hematopoiesis
		c. Heart and circulatory system
		d. Immune system
		e. Spleen
		f. Urinary system and urethra
		g. Reproductive system—testis
		h. Reproductive system—ovary
		i. Skeletal system
		j. Limbs
12	Endoderm formation and its derivatives	a. Digestive system
		b. Respiratory system
		c. Thymus
		d. Parathyroid
		e. Thyroid
13	Structures developing from mesenchyme or multiple germ layers	a. Adrenal glands
		b. Eyes
		c. Ears
		d. Face and neck
14	Intrauterine growth