Liersel Einstein was the first child of Albert and his first wife, Mileve Maric. However, the weird thing is that there’s no official record of her except in letters between Einstein and Maric. She’s believed to have been born with mental disabilities and in the last letter written about her in 1903, Einstein writes, “As what is the child registered? We must take precautions that problems don’t arise for her later.” This suggests that they were planning on giving her up for adoption.