The baby boy recently received the title from the Guinness World Book of Records, which said that he was conceived at a fertility group in Queensland, Australia, on Sept 24 last year.
According to The Mirror UK, Xavier was born on June 17 this year to Australian couple Alex Powell and Vi Nguyen via in-vitro fertilisation (IVF).
When he was 15 years old, Mr Powell was diagnosed with a rare type of cancer that affects the lymphatic system – Hodgkin’s lymphoma.
Although he was only a teenager at the time, his stepmother had advised him to freeze his sperm before undergoing chemotherapy.
Sperm cells can be easily damaged by chemotherapy as it kills cells that divide rapidly, an article by the American Cancer Society explains.
The treatment may also reduce the number of sperm cells, reduce their quality, and cause the cancer patient to suffer from infertility.
After what Mr Powell described as “an awkward session” at the sperm bank, a sample of his semen remained frozen in the facility for over two decades.
He subsequently made a full recovery from cancer and later met his wife.
The couple decided to have a child through IVF in late 2013, and spent nearly a year as well as half of the frozen sperm before getting pregnant with Xavier.
On his son’s birth, Mr Powell said in an interview with 9News: “For me, it’s that sort of feeling in life you want to relive every moment if you can.”
He added that they might try for a second child using the same method.
Meanwhile, a baby girl born in the United States in 2009 is believed to have been the titleholder of ‘World’s oldest baby’ before Xavier’s arrival.
ABC News reported that she was born 22 years after her father Chris Biblis froze his sperm while battling leukaemia in 1986.
According to medical experts, sperm frozen at -196 degrees Celsius can be stored and used after an indefinite period of time.
In a report by The Guardian UK, Alan Pacey, an andrologist at Sheffield University elaborated: “There’s very little happening at the cellular level. There’s no enzymatic activity, no DNA transcription and everything metabolic is switched off.”