During the development of the fetus there is frantic cell growth and division activity. It is interesting to note that the body cells later loose this ability to multiply rapidly with the exception of the dermal papilla in the hair follicle. The dermal papilla and associated epidermal cells retain this ability for most of the adult life.
It is not surprising that the establishment of a dermal papilla during embryogenesis (early stages of embryo formation) is vital to the subsequent development of all hair follicles and associated modified structures.
Just so that we have a frame of reference, the table below summarizes the stages of fetal development:
| End of month | Typical changes |
| 1 | Eyes, ears, and nose not yet visible. Backbone starts to form. Heart forms and begins beating. |
| 2 | Eyes far apart, eyelids fused. Arms and legs almost formed. Internal organs continue to form. Bones start to develop (ossification). Fingers are formed. |
| 3 | Eyes almost fully formed but eyelids still fused. Appendages are fully formed and nails start to develop. |
| 4 | Face takes on human features and hair appears on head. Skin bright pink. Continued development of body systems and internal organs. |
| 5 | Head less disproportionate to rest of body. Fine hair (laguno hair) covers the body. Skin still bright pink. Rapid development of body systems. |
| 6 | Eyelids separate and eyelashes form. Skin still pink and wrinkled. |
| 7 | Head and body even more proportionate. Skin wrinkled and pink. |
| 8 | Subcutaneous fat is deposited. Skin becomes less wrinkled. |
| 9 | More subcutaneous fat accumulates. Laguno hair is shed. Nails extend to end of fingers. |