The family of Mao Xinyu, Mao Zedong's grandson, has celebrated a month after the birth of their newborn son Dongdong, the Beijing Youth Daily reports. It is a Chinese tradition that relatives celebrate - usually with a family feast - when a child is one month old. Dongdong was born in a Beijing hospital on December 26 - the 100th anniversary of Chairman Mao's birth. The newspaper said the family held a small private party yesterday for Dongdong but did not say whether government officials were invited. The report said Dongdong was merely a nickname for the baby boy and a proper name would be chosen when he was older. The nickname was chosen by the boy's grandmother, Shao Hua, who said it was originally meant to match the last character of his great grandfather's name and to mean that he was born in the winter. However, it was later changed to use the same two characters because the family felt that winter was inappropriate. Mao's family has made few public appearances. However, Mao Xinyu, 32, attended a book signing ceremony last November when he released a new book about his grandfather - founder of the People's Republic. Mao Xinyu is the son of Mao Anqing - the second son of Chairman Mao. Mao Xinyu is now studying at the Chinese Academy of Military Science. He has published several books about his family and spent the past four years writing the book on his grandfather.