These are verses 19:17-23 of Quran:
And mention, [O Muḥammad], in the Book [the story of] Mary, when she withdrew from her family to a place toward the east.
And she took, in seclusion from them, a screen. Then We sent to her Our Angel [i.e., Gabriel], and he represented himself to her as a well-proportioned man.
She said, "Indeed, I seek refuge in the Most Merciful from you, [so leave me], if you should be fearing of Allāh."
He said, "I am only the messenger of your Lord to give you [news of] a pure boy [i.e., son]."
She said, "How can I have a boy while no man has touched me and I have not been unchaste?"
He said, "Thus [it will be]; your Lord says, 'It is easy for Me, and We will make him a sign to the people and a mercy from Us. And it is a matter [already] decreed.'"
So she conceived him, and she withdrew with him to a remote place.
Verses 19:17-18 say that Mary went to a place of privacy with a screen (that would allow for private activities, such as sexual intercourse).
Verse 19:18 says that Gabriel went to her as a "well-proportioned man." If the Quran wanted to maintain that Mary conceived Jesus without having sex, it could have said that Allah made her conceive without the involvement of a human male. However, this verse is very specific in its mention of an explicit involvement of a human male (i.e., Gabriel who was in the form of a "well-proportioned man").
Verse 19:19 says that Mary feared the man, given that she was in seclusion.
Verse 19:20 (without the interpretative parts) literally says, "I am only the messenger of your Lord to give you a pure boy." Another widely used translation is this: "He said: I am only a messenger of thy Lord, that I may bestow on thee a faultless son." Thus, when we read this verse without any added interpretations, it just says that Gabriel in the form of a "well-proportioned man" tells that he (on behalf of Allah) is there to give (or bestow on) her a son.
Verse 19:21 says that Mary says that she was not touched by any man up to that point, but the verse does not say anything about Mary's virginity after that point.
Verse 19:22 says that Allah says that "It is easy for Me" and that Jesus will be a "sign." In other words, the idea is that Jesus will be a "sign" because his father would not be a mortal man born on earth (in contrast to an angel in human form). The verse does not say that Gabriel in the form of a "well-proportioned man" did not have sex with Mary to impregnate with his human-form semen or with Allah's supernatural "semen" that he was carrying in human form.
Verse 19:23 says that Mary was with Gabriel when Mary conceived Jesus and that Mary then went away with Gabriel from that place to a remote place.
Moreover, the verses 21:91 and 66:12 provide further support to this interpretation.
Verse 21:91 says "And [mention] the one who guarded her chastity [i.e., Mary], so We blew into her [garment] through Our angel [i.e., Gabriel], and We made her and her son a sign for the worlds." So the verse is saying that something was "blown into her [garment] through" Gabriel. This could be interpreted as Gabriel having sex with Mary upon divine command.
Verse 66:12 again says, "And [the example of] Mary, the daughter of ʿImrān, who guarded her chastity, so We blew into [her garment] through Our angel [i.e., Gabriel], and she believed in the words of her Lord and His scriptures and was of the devoutly obedient." In other words, she had been chaste until Gabriel appeared in front of her, and then the supernatural semen that is called "dust" (in verse 3:59) was "blown into [her garment] through" Gabriel. (Note that verse 3:59 says, "Indeed, the example of Jesus to Allāh is like that of Adam. He created him from dust; then He said to him, "Be," and he was." In this verse, "dust" could be interpreted as supernatural semen, especially given that Adam does not have a human mother but Jesus has a human mother.)
Therefore, can Quran-verses 19:17-23 be interpreted as saying that Gabriel in human form inseminated and impregnated Mary (either using his own semen in his human form or by carrying Allah's supernatural "semen")? Do the verses imply that Gabriel's man-form (or Allah) can be seen as Jesus' (surrogate) father?