It's Mary who is claimed to have been born of an "immaculate conception" - a Catholic dogma developed in the 1800s when scientists discovered that an embryo required a female egg rather than simply being the result of male sperm. The term is not used in reference to Jesus, which is called a "virgin birth".

It is hard to see the new dogma of Mary's Immaculate Conception as an isolated and purely religious event. Although the dogma was declared a few years before the details of conception were known and the implications of von Baer's discovery of the female egg was not yet fully understood, the fact that the pope felt the need to make this aspect of Marian tradition part of official teaching can be viewed as a response to the developments in modern science in general and embryology in particular.

By the way, the "virgin birth" theme - or miraculous births, usually involving gods - was common to many religions/mythologies.