The Queen of Pop may already have four of her own kids - five, if you count 22-year-old boytoy, Jesus Luz - but The Sun is reporting that the 51-year-old singer is ready to open her heart to another one. Luz seems to be open to the idea, saying that becoming a daddy would be "his greatest adventure." Madge seems to agree; the tabloid says she agrees and thinks Luz would make a "fantastic dad." She's already mom to two of her own kids, Lourdes Leon, 13, and Rocco Ritchie, 9. Plus, she adopted Malawian orphans David Banda and Mercy James, both 4. But can she get into the groove of being pregnant? A close pal told the tabloid, "She knows that, at 51, it's going to be harder to conceive naturally. But she is Olympic-athlete fit and is ready for the challenge." She also ought to know that a huge chunk of her fortune will go to having IVF...