Explain That!

Evan (age 5), is learning Bible vocabulary words from the A Beka 1st grade curriculum and Primary Bible Reader.
This week some of the words learned were from Luke & the story of the birth of Jesus: “Virgin” and “conceived” were among them.
I tried to give these words child-friendly and 5-year-old-age-appropriate definitions (now tell me, exactly how do you do that?).
A couple of hours after explaining that “conceived” meant “to be pregnant”, Evan was playing with his 3 year old sister Ella, when he (referring to her large toddler-stage pop-belly) exclaimed, “It looks like Ella has probably conceived.”