The story investigateislam quotes basically narrates that during The prophet’s mothers pregnancy light came out of her and it shined the palaces of Syria. Here is the link that Investigateislam uses on his video from al-islam.com.
Response
This story is explained thought hadiths of our prophet Muhammed. In Musnad Ahamd, Hadith number 16537. Here is the English translation of the hadith.
‘Irbad ibn Sariyah al-Sulami reported, “I heard the prophet peace be upon him- saying, ‘I, the Servant of Allah, am indeed the Last of the Prophets in the mother Book (Umm al-Kitab) even when Adam was in his clay form. Let me inform you the meaning of this. It is that my father Abraham prayed for me and Jesus gave the good news about me to his people. My mother saw in her dream that a light came out of her that shined the palaces of Syria. Thus used to see the mothers of the Prophets -peace be upon them.’”
http://hadith.al-islam.com/Display/Display.asp?hnum=16537&doc=6&IMAGE=%DA%D1%D6+%C7%E1%CD%CF%ED%CB
As we see, the story in its entirety indicates that this was a dream, this did not literally take place. But even if it was literal, there should be no problem, Christians believe God came out of a woman’s vagina, so why cannot light (a natural creation) be emitted from a woman’s belly? This is not a bad thing, it’s a miracle, just like Christians believe their God walked on water. Some Christians are hypocrites, they accept miracles for their own religion, but they do not allow that right to other belivers.