Thank you.
It is cancer, and I realise many reading this will have also lost loved ones to cancer 
but I'm sure you all know there are cancers and cancers and some are more likely to have a positive outcome than others.
I hesitate to say this as I realise you can't generalise about grief but two points.
Firstly, some have told me they lost their parents and are sad but not devastated.
There is a huge difference in losing a parent as a child and as an adult, even a young adult. For children the instinct is often to keep things as normal as possible. I feel this is unwise, as it gives children an impression nothing much has happened. I remember crying after the funeral and someone disparagingly asking me 'what was I making such a big fuss about.' 
For a child, parents are the centre of the world and for this to be removed it is enormously painful.
If you came through that and don't identify with my explanation it may be because your surviving parent was in a fit state to deal with your grief. Unfortunately mine was not - partly because he was also unwell.
My second point is that losing one parent is awful. But until you lose both I don't think you really can fully appreciate the sense of discombobulation and loss of identity even. A sense of belonging to a family unit, even as an adult, is an important one.
Now there is an age where obviously you expect this and as Claudius tells hamlet 'your father lost a father' but nowadays, most people expect to live to a good age, and most people generally don't lose both parents until their forties, fifties and even beyond. I had buried both mine when many of my friends were also mourning their grandparents.
I'm also conscious it will lead to a further disconnect further down the line - when my friends do start to lose their parents - far from identifying and understanding I think the general feeling is my losses are so far away as to be meaningless.
Not a day has gone by I haven't thought about both my parents. I'm not sure I miss them any more - my mother certainly not as I struggle to remember her.
But has it left its mark? Yes; I wish I could say it has not and that I shrugged and smiled and realised that my parents would want me to carry on. But it has left its mark.
Small ways - as a student doing a college course we had to leave our placements and I had nowhere to go in holidays. It was assumed most students would go 'home' I of course could not so was homeless. I slept in my car or on friends' sofas and spent Christmas Day one year in the early 2000s alone eating salt n vinegar crisps for Christmas lunch. I know that shouldn't matter now but it does. My days as a young woman that should have been filled with fun and happiness and heartbreak were instead spent trying to find where I fit into the world. I graduated and no one came. A hundred and one ways you are reminded of what you don't have.
And because of the lack of a safety net there is a tendency to cling tightly to what you know.
I'm digressing because I'm trying to explain how different it is to someone in their twenties very sadly losing one parent. That's awful, it's heartbreaking and you have my compassion. But it is not the same as what I went through and that's why I worry so about potentially putting any future children through it.