H.R.H Princess Ubolratana was born on April 5, 1951 the only son H.R.H Crown Prince Maha Vajiralongkorn was born on July 28, 1952. H.R.H Princess Maha Chakri Sirindhorn was born on April 2, 1955 and H.R.H. Princess Chulabhorn was born on July 4, 1957.