Bobbi Kristina Brown has allegedly left her family reeling with her plans to start a family.

The only biological child of the late Whitney Houston, Bobbi shocked the world when she announced she was planning to marry Nick Gordon - who Whitney raised as her son.

The pair wed in secret earlier this month and are now keen to have children.

"They want to have a baby as soon as possible. After a few tough years, it seems Bobbi wants a happy ending. But her grandmother is beside herself with worry," a source revealed to British magazine Grazia.

Bobbi had previously claimed that her grandma Cissy was fine with the marriage, as well as saying her mother would have approved. Friends insist this is not the case.

Insiders say Cissy was left "reeling" by the news, and the baby plans will only make things worse.

After Bobbi's mother Whitney tragically drowned in February 2012, the 20-year-old was linked to Nick.

Nick had moved in with Whitney and her ex-husband Bobby Brown when he was 12, as his mother could not care for him.

Although the singer never formally adopted Nick, he was thought of as a part of the family.

"It's not that Cissy dislikes Nick, but she thinks Bobbi has rushed into things and finds it odd because she still sees Nick as Bobbi's brother," the source added.

In an open letter to Bobbi that was released last year, Cissy told her granddaughter how she wished she had waited before rushing into the relationship.