The science requires authenticity for every action when that is not delivered they are termed as "unscientific". Now, coming back to the topic about immaculate conception .Normally, to conceive a baby male and female factor is essential. But,there is an exception to this rule. Have you seen flies which erupts from the ground, when thunder clouds looms over the place, after a dry summer period just before rains? Have you seen worms inside a fruit? Now, tell me who "inserted" it?
A story from Mahabharata would throw some light on this topic. Kunti, mother of pandavas , before marriage, chanted a mantra(possibly to test the power of the mantra) in devotion to Sun god and got conceived. No physical union was involved.
