The Earth's population continues to grow. Will there come a day when there will be more space and/or food for everyone? (The Spirits’ Book Q. 686)

          Will the human race cease to exist on Earth in the future? (The Spirits’ Book Q.689)

          Will other races of humans exist on Earth in the future? (The Spirits’ Book Q. 689)

          What distinguishes the primitive human beings from todays? (The Spirits’ Book Q.691)

          It is correct to try to work on improving the animals and the plants through science? (The Spirits’ Book Q.692)

          Can humans regulate the reproduction of living beings, avoiding excessive in number? (The Spirits’ Book Q. 693 issue - a)

          The custom of marriage, i.e., of human beings to unite in lasting relationships with the objective of constituting a family, can be considered a kind of progress? (The Spirits’ Book Q. 696)

          Can Spiritists divorce? Why? (The Spirits’ Book Q. 697)

          What is celibacy? When does it have value before the Divine laws? (The Spirits’ Book Q.698 and 699)

          What is polygamy? What about monogamy? Which one is according to the God’s laws? (The Spirits’ Book Q. 701)