You were asked to identify three eight-letter words in English which contain exactly the same letters, are intimately related in subject matter (reproduction), but are completely unrelated to one other linguistically, being a remarkable example of evolutionary convergence.
All three are from the ancestral Indo-European language, and all three from different roots.
natal comes from the Indo-European root gene-, source of many many words dealing with birth and family, from kin to general to indigenous to pregnant, including the Latin participle gnatus/natus (born), whence natal. Because they come from the same root, kin/general/indigenous/pregnant are cognates.
paternal comes from the Indo-European root peter, source of both Latin pater and English father.
parental comes from the Indo-European root pere, source of words dealing with production and fertility.
There is one remote connection between the three words. It is possible that the root of parental is in turn derived from the same root as the pre- in prenatal. Almost every Indo-European language, from Russian to Gaulish to Sanskrit, has an abundance of prepositions and prefixes and roots deriving from the Indo-European per. We cannot afford to forget that this is by far the foremost, primary, preeminent, and paramount prototype of the words proven to have descended to us from the linguistic paradise of our first privileged forefathers.
In the above, note that the Indo-European initial p- becomes
f- in Germanic languages like
In case you couldn't guess, language is one of my other enthusiasms.