The "Ease of Pregnancy and Age Graph" is a graph in which 22 years old is the peak of the ease of pregnancy and has been declining sharply since then. It was published in.However, the graph originally posted was found to have an inaccurate source display and the curve had been tampered with, so the Ministry of Education, Culture, Sports, Science and Technology replaced it with another graph.After that, it was pointed out that the replaced graph was also inappropriate, and the Japanese Society of Reproductive Medicine commented that "this graph is appropriate for the graph that has been used for many years", but based on the original material. No discussion was held and the circumstances remained unclear.

To clarify the history of "Ease of Pregnancy and Age Graph," Associate Professor Tanaka examined the original data of the graph, the 1978 demographic paper and the literature that cited it.As a result, it was found that the 1978 paper data is an estimate limited to early-married women who were married by their early twenties, and is likely to confuse changes in sexual behavior over time.This issue has been pointed out by experts but has not been revalidated.In addition, the graphs used in the material are not from this original text, but from a great-grandchild from the 20 paper, which is a further copy of the graph from the 1989 paper that was processed and critically cited. It was also found that the curve was deformed, creating the impression that the data was unfounded, “1998 years old peaked”.

　Associate Professor Tanaka suggests that he has used problematic data uncritically, repeated inaccurate citations, and that there are deep-seated problems in this field of study that have neglected to check the source material and research history. I am.