Rob Kardashian said that he plans to be married before having children, unlike his older sisters, Kim and Kourntey.

News of Kim Kardashian’s pregnancy was a New Year’s Eve surprise. The reality star confirmed that she is expecting with boyfriend of eight months, Kanye West. The rapper announced the news during his Dec. 30 concert, referring to Kardashian as his “baby mama.”

Kourtney Kardashian has two children, Mason, 3, and Penelope, 6 months, with boyfriend, Scott Disick. They aren't married.

"I'm so proud of my sisters, but I'll be married before I have a baby," Rob Kardashian told People magazine at the Ciroc Vodka New Year's Eve Countdown at STK Miami on Monday.

Kim Kardashian is actually married -- to NBA player Kris Humphries -- whom she wed in August 2011 and was married to for 72 days before filing for divorce.

While the two have been separated for more than a year, their divorce proceedings have not yet started, and may not begin until June, according to Radar Online.

Kim Kardashian is reportedly refusing to submit to Humphries’ demand for an annulment, for fear that admitting their marriage was a fraud could damage her image.

"Unless Kim Kardashian gives in to Kris' demand that she admit the marriage fraudulent, the divorce proceedings will still be ongoing and she will still be legally married to him when she gives birth,” a source told Radar.

Meanwhile, Rob Kardashian, told People magazine that Kim Kardashian told each of family members about her pregnancy individually, and said she and Kanye West are not yet thinking about marriage.

"I think everyone is just excited about and focused on the baby right now," he told the magazine.

"Kim and Kanye are over the moon happy," he added. "I'm so excited to be an uncle again!"

Kourtney Kardashian and Scott Disick also have no plans to get married; she reportedly recently turned down a proposal from him, according to the Daily Mail.

The newspaper also noted that episodes of the family’s reality show, “Keeping Up With the Kardashians,” have depicted Rob Kardashian encouraging his sister to make Disick feel more included in her life.

Rob Kardashian, however, is no stranger to out of wedlock pregnancy himself. During his split with Rita Ora, the Arthur George designer posted a tweet suggesting that he had made the British singer pregnant, but he quickly deleted the tweet.

During the last season of Khole Kardashian’s reality show “Khloe & Lamar,” her brother reportedly reconnected with an “old friend,” video model, Rosa Acosta, during a trip to San Diego; she apparently later discovered she was pregnant that with a child that could have been his.

Rob Kardashian had said that he planned to take responsibility for the baby; however, Acosta later suffered a miscarriage, reports said.