What does the phrase, "From forth the fatal loins of these two foes" mean?

The phrase, "From forth the fatal loins of these two foes" in William Shakespeare's "Romeo and Juliet" announces to the audience that the unfortunate children born to the two warring families, the Capulets and the Montagues, are fated or destined to fall in love and die because of it. The next line completes the idea, "A pair of star-crossed lovers will take their life ..."

The lines are spoken by the chorus in the prologue to Shakespeare's classic romantic tragedy. The prologue is written as a sonnet, a poetic form which often deals with themes of love and tragedy, and was very popular in 16th century England, when Shakespeare was alive.