London, Oct 19 (ANI): Republican vice-presidential nominee Sarah Palin burst out laughing when her 17-year-old daughter Bristol told her she was pregnant, it has been revealed.

The US Republican hopefuls bizarre reaction has been revealed by Sherry Johnston, the mother of Bristols 18-year-old fiance Levi.

Johnston has revealed that when a distraught Bristol waved the pregnancy test stick in her face, shouting Its true, mom, I amhaving a baby, anti-abortionist Palins hysterics just got worse because she thought it was all a joke.

Sarah was at home when Levi and Bristol burst in with the pregnancy stick, News of the World quoted Johnston, as saying.

But Sarah started laughingand when Levi and Bristol waved the evidence at her she was was giggling so hysterically she couldnt stop.

They had joked a number of times about having a baby, so she thought they were kidding. But when she finally realised it was real she was shocked and her face dropped, she added.

Johnston has also revealed that the Alaska governor never taught her daughter about safe sex, insisting not doing it was the only way to avoid babies.

Besides this, Johnston has revealed how Palins world nearly crumbled when rumours erupted that she had been cheating on her oil worker husband Todd.

Sarah was heartbroken. It hurt her more than anything else that had been thrown at her because she loves Todd and swore blind to all the family the rumours were not true. She gathered them all together crying, and said, We cannot pay attention to these things and we must stick together as a family. Everyone has a breaking point, but as ever Sarah has bounced back, she added. (ANI)