Luke 1:18; 24,25
And Zechariah said to the angel, "How shall I know this? For I am an old man, and my wife is advanced in years."
After these days his wife Elizabeth conceived, and for five months she kept herself hidden, saying,
"Thus the Lord has done for me in the days when he looked on me, to take away my reproach among people." (ESV)
Luke 1:18; 24, 25
The Jewish priest Zechariah and his wife were an older couple who apparently went through most of their lives without having any children. Now, in their latter years, an angel of the Lord came to announce that they would have a son who would grow up to be a mighty prophet of God (John the Baptist). This was a difficult thing for Zechariah to believe.
But, as we see here, and many other examples throughout the Scriptures, it is God opens and closes the womb. It is God who takes a dead womb and brings life to it.
For the LORD had closed all the wombs of the house of Abimelech because of Sarah, Abraham's wife. (ESV)
The LORD visited Sarah as he had said, and the LORD did to Sarah as he promised.
And Sarah conceived and bore Abraham a son in his old age at the time of which God had spoken to him. (ESV)
Conception is an act of God. That is the bottom line. All human conceptions happen because God sovereignly wills them to happen.
The Bible also does not make any distinction between a baby inside the womb, or a baby outside the womb.
God can also cause a young woman, who had not have any sexual relations with any man, to conceive a child in her womb.
Behold, children are a heritage from the LORD, the fruit of the womb a reward. (ESV)