Thomas Aquinas

“ And as soon as Adam had attained to that happy state of seeing God in His Essence, he would have become spiritual in soul and body; and his animal life would have ceased, wherein alone there is generation. ”

“ Further, Anselm says (Cur Deus Homo i, 18) : "If our first parents had lived so as not to yield to temptation, they would have been confirmed in grace, so that with their offspring they would have been unable to sin any more." Therefore the children would have been born confirmed in righteousness.
Objection 3: Further, good is stronger than evil. But by the sin of the first man there resulted, in those born of him, the necessity of sin. Therefore, if the first man had persevered in righteousness, his descendants would have derived from him the necessity of preserving righteousness. ”

“ Hence whatever accidental qualities result from the nature of the species, must be alike in parent and child, unless nature fails in its operation, which would not have occurred in the state of innocence. But individual accidents do not necessarily exist alike in parent and child. ”