Likutei Moharan 53:1/ליקוטי מוהר"ן נ״ג:א׳

1In the main, the ability to have children is dependent upon the heh, in the aspect of “Heh (Here) you have seed” (Genesis 47:23). Thus Avraham and Sarah did not have children until they attained this heh. <As the Sages, of blessed memory, taught: Avram could not father offspring, but Avraham could father offspring (Bereishit Rabbah 44:10) .>

2This is because the ability to have children comes essentially through the daat, in the aspect of “Adam knew his wife” (Genesis 4:25). Hence, “a child cannot bear offspring” (Sanhedrin 68b), <because he lacks daat that is whole>. And the essence of daat is that he makes use of his daat—i.e., he converts his intellect from potential to actual. For a child also has daat, but a child’s daat is still in potentia and not actus, because he has not made use of his daat and has not converted it from potential to actual.

3Yet someone whose daat is whole—because he has converted it from potential to actual, and has attained with his daat that which is possible for the human mind to attain with its daat—he is then close to the daat of the Holy One, and there is no difference between human daat and the daat of God other than five things, as is brought. Then his daat nourishes from God’s daat, which is the aspect of heh, and he can then father offspring.