A brother and sister with cystic fibrosis could die if they share toys due to the risk of infection, their parents have revealed.
Sienna Woods, two, and Noah Woods, one, are unable to kiss each other - but the adorable siblings are difficult to keep apart.
Their mother Shelby Woods, 25, from Burscough, Lancashire, has to rigorously clean everything with disinfectant and can't allow her children to play in sandpits.
Cystic fibrosis (CF) sufferers are a danger to each other due to cross-contamination of bugs they grow in their own lungs.
The incurable condition affects the internal organs, especially the lungs and digestive system, clogging them with thick, sticky mucus.
Sienna Woods, two, and Noah Woods, one, who both have cystic fibrosis, are unable to share toys or kiss each other due to the dangers of cross-contamination
Mother Shelby Woods, 25, from Burscough, Lancashire, has to rigorously clean everything
Sienna and Noah were each diagnosed with CF shortly after they were born
Ms Woods said: 'It's so difficult to stop Sienna and Noah being together. It makes me sad that they can't be so affectionate with each other.
'We allow them to hug but they're not allowed to kiss because of the cross-infection risk. There's a possibility they won't get be able to fight it and could actually die.
'If Sienna is playing with a toy we have to make sure Noah doesn't pick it up and disinfect it before he does.
Sienna and Noah were each diagnosed with CF - a debilitating, life-shortening condition - shortly after they were born.
More than 10,000 people in the UK have it and there's currently no cure. Half of the people in the UK with it will die before they're 31.
Receptionist Ms Woods said they were shocked when they found out Sienna had CF three weeks after she was born, having been unaware there were any carriers in her family.
Ms Woods said if one of the children is playing with a toy, it must be disinfected before the other child picks it up. The children pictured at home
People with cystic fibrosis (CF) are normally kept apart due to the danger of cross-contamination of bugs they grow in their own lungs
CF affects the internal organs, especially the lungs and digestive system, clogging them with thick, sticky mucus
They were told Noah had a 25 per cent chance of having it - before discovering he, too, did have the condition.
CF patients grow different bacteria in their lungs which are usually harmless to people who don't have CF, though they can be harmful to those who do.
Although coping well on a daily basis, the problems occur when the children get sick - struggling with wet coughs that bring up mucus.
They have to take around eight different medicines a day and make regular visits to the hospital as well as having daily physiotherapy.
Ms Woods said: 'They have separate branded drinks bottles, separate cutlery and bowls when they eat.
'I have to watch them constantly. They're not allowed to play in sandpits or jump in puddles because of the risk of spores.
Cystic fibrosis is caused by a faulty gene that a child inherits from both carrier parents.
The gene, known as the cystic fibrosis transmembrane conductance regulator (CFTR), is responsible for controlling the movement of water in and out of cells.
The fault leads to the mucus produced throughout the body becoming thick and building up in the lungs and digestive system.
Classic complications of the condition, which tend to present in infancy, include chronic infections, breathlessness, digestive problems and even infertility.
There are approximately 30,000 cases of CF in the US and nearly 11,000 people in the UK are known to suffer.
No cure currently exists and figures suggest half of sufferers will die before they're 31.
Source: The Cystic Fibrosis Foundation
The children have to take around eight different medicines a day and make regular visits to the hospital as well as having daily physiotherapy
Ms Woods, a receptionist, with a picture of Sienna when she was in hospital as a baby. She was diagnosed with CF three weeks after birth
Ms Woods said she is fighting a daily battle for her children. Pictured, Sienna as a baby
'They're getting to that age where they want to have a sleepover but we can't allow them to share a bedroom which is really upsetting.
'I also try and keep them really clean. I bathe them in the morning separately and then again in the evening to make sure any bugs are washed off.'
Ms Woods said she is too scared even to book a summer holiday as she doesn't like to plan too far ahead.
She said: 'With CF you fight daily battles so having to fight this one as well it's exhausting.
'Their life expectancy is between 35 to 40 years but we don't know from one day to the next what might happen.
'They could be fine and then the next day their lung capacity could drop and that could be it.
'We try not to plan too far ahead - only a week or