The 55-year-old comedian became a father for the first time in May after his girlfriend Cath Mason gave birth to Buzz Cody.
Skinner said that, while he would like a bigger family, he realises he is running out of time.
"I'd be happy to have a bundle more, but the clock is ticking," he told The Sun "I am not planning on squandering any money on contraception in the near future. I am a Catholic, it's pot luck."
He added that he finds it difficult to make his son like his jokes, saying about children: "They are an incredibly tough audience.
"Getting a laugh or a smile out of them is hard work, it's like doing the Brits."
Skinner's BBC show Room 101 was recently renewed for a second series with him as host.
Watch a clip from the last series of Room 101 below: