conception-Idiom needed

[besthost]

Let's imagine a woman is gonna have a baby, but she does not know exactly how it's possible, because she hasn't slept with anybody within 9 months.

And some guy says: She must have slept with someone. There's no such thing as ".................. conception". I need to fill in the blank.

[Anglika]

"immaculate"

[Barb_D]

Actually, you'll find 95% of the people use it that way, but idea of "immaculate conception" is that Mary, the mother of Jesus, was born free from original sin, and was therefore a suitable vessel for the birth of Jesus.

However, just about everybody who uses the phrase "immaculate conception" uses it to mean a pregnancy that occurs without sex.

[besthost]

Thanks very much!