וַיִּֽהְי֤וּ שְׁנֵיהֶם֙ עֲרוּמִּ֔ים הָֽאָדָ֖ם וְאִשְׁתּ֑וֹ וְלֹ֖א יִתְבֹּשָֽׁשׁוּ׃
那人和他的妻子，兩個人都赤身露體，卻不覺得羞恥。
Rashi
ולא יתבוששו AND THEY WERE NOT ASHAMED — for they did not know what modestly meant, so as to distinguish between good and evil. Although he (Adam) had been endowed with knowledge to give names to all creatures, yet the evil inclination did not become an active principle in him until he had eaten of the tree, when it entered into him and he became aware of the difference between good and evil.
Sforno
And they were not ashamed. They used their limbs solely for the service of their Maker, not the pursuit of base pleasures. Therefore they considered marital relations no different than eating and drinking and their reproductive organs no different than their mouth or hands.