<Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> An oogonium (plural oogonia) is a small diploid cell which on maturation forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes . </P> <P> Oogonia are formed in large numbers by mitosis early in fetal development from primordial germ cells . In humans they start to develop between weeks 4 and 8 and are present in the fetus between weeks 5 and 30 . </P> <P> Normal oogonia in human ovaries are spherical or ovoid in shape and are found amongst neighboring somatic cells and oocytes at different phases of development . Oogonia can be distinguished from neighboring somatic cells, under an electron microscope, by observing their nuclei . Oogonial nuclei contain randomly dispersed fibrillar and granular material whereas the somatic cells have a more condensed nucleus that creates a darker outline under the microscope . Oogonial nuclei also contain dense prominent nucleoli . The chromosomal material in the nucleus of mitotically dividing oogonia shows as a dense mass surrounded by vesicles or double membranes . </P>

When are oogonium cells produced in a female