>>genetic diseases are 'recessive' and are not passed on to every child
That's the point of the article though, it's nothing to do with the father's DNA and chance.
Mitochondrial DNA always comes from the mother and does not have a chance to be paired with the father's DNA.
This yields two concequences:
1. If a mother has a disease linked to mitochondrial DNA then the child is 100% sure of having it, since the egg's mitochondia IS the mothers
2. m-DNA doesn't mutate via sex, the disease will not 'bred' out of the population - it ranomly mutates at a much slower rate
The reason this is significant is that m-DNA doesn't alter the charaterastics of the person (in terms of looks, build, eye colur). And so man has crafted a way of ensuring the survival of the mother's defining genes, inspite of a faulty (hard to repair through natural selection) mechanism.
>>so you could remove or add 'gay' DNA
No - there's no such thing as gay mitochondria