"As ... the Reformed philosopher Gordon Clark observes, the traducian understanding of original sin is also taught by Christ in John 3:6, when Christ speaks of Nicodemus’s unregenerate soul as born of his parents. Clark notes that the Greek noun sarx (i.e. “flesh”) in relation to gennao (the Greek word for “birth”) clearly conveys this idea of a depraved soul in distinction from the corporeal body, which means that the propagation of the human species is not only corporeal, but spiritual and mental also."

https://knowingscripture.com/articles/on-the-salvation-of-children-who-die-as-infants