birth defect vs anomaly

birth defect and anomaly both are nouns.

Word	Noun	Adjective	Verb	Adverb
birth defect	Yes	No	No	No
anomaly	Yes	No	No	No

As nouns, anomaly is a hypernym of birth defect; that is, anomaly is a word with a broader meaning than birth defect:

Other hypernyms of birth defect include defect, anomalousness.

birth defect (noun)	anomaly (noun)
a defect that is present at birth	(astronomy) position of a planet as defined by its angular distance from its perihelion (as observed from the sun)
	a person who is unusual
	deviation from the normal or common order or form or rule