Halakhah for Berakhot 29:21

Also, he should check if he has to go to the bathroom before prayer, as Rabbi [Yochanan] says (Brachot 15a): "One who wants to take upon himself the yoke of heaven fully — he should go to the bathroom and wash his hands, and he should put on Tefillin, and he should say Sh'ma, and he should pray [the Shemoneh Esreh]." And a person should become accustomed to go to the bathroom in the morning and in the evening, it is being careful and clean. And one only has to check himself. But if he checked and nothing comes out, even if he imagines that he needs to go to the bathroom — he is considered a "clean body" anyway, and is required to pray. And if, God forbid, the time for saying Sh'ma passes because of this [having to go to the bathroom] — the Torah wasn't given to angels, it was given to humans — what can he do? Many people make a mistake about this, thus one should warn them. And he shouldn't walk around with parts of his body naked. And he shouldn't walk around barefoot, since there is nothing more offensive than someone that walks around barefoot.

That is that He commanded us to be fruitful and multiply, with the intention of preserving the species. And that is the commandment of piryah verivyah. And that is His, may He be exalted, saying, "And you, be fruitful and multiply" (Genesis 9:7). And they have already explained (Berakhot 16a) that a groom is exempt from the recitation of Shema on account of being busy with [this] commandment. And the laws of this commandment have already been explained in Chapter 7 of Yevamot. But women are not obligated in this commandment. And in the explanation, they said (Yevamot 65b), "A man is commanded to be fruitful and multiply, but not a woman." (See Parashat Bereishit; Mishneh Torah, Marriage 15.)