It would seem that this is likely not about Mary being a virgin when Jesus was born but about the tradition that she remained so forever afterwards.
The latter is merely a tradition unsupported by Scripture. As is the belief that she was somehow born without sin herself (which only puts any perceived issues with Mary having a normal human nature off on her own mother, never mind cutting her own familial ties with the different guys, from Abraham on, who had expressly been given the promise that their seed was the one who was promised).
That is how I read it also.
That comment makes no sense at all. Mary wasn't the product of a virgin birth.