Most of us are aware of sibling rivalry. But I'm not sure there is a term for the condition suffered by my worst parent, other than "pure jealousy" of the achievements of her daughter.
This parent was a trophy wife. She was a kind of prototype WAG with cascades of long, bleached blonde hair, industrial quantities of mascara and short skirts. There was no doubt she turned heads, and some question - among the less charitably inclined at the school gate - of whether she also turned tricks.
However, her daughter was a gem of a kid - polite, diligent and very scholarly. She was also, to be frank, plain. This attribute didn't fit into WAG world and her mother could not come to terms with what she had produced. She could not appreciate the differing talents that her daughter possessed.
This was a great shame. The child got no encouragement and no recognition for her achievements. Instead, every time I met the mum and started to praise her daughter, she would flutter her eyelashes (which were so big that she almost took off) and change the subject.
Quite simply she was jealous. She was so used to being the centre of attention that she couldn't hack it. She was being eclipsed by her daughter and didn't fancy life in the shade.
Despite this, her daughter maintained her motivation and progressed well and, I assume, went on to great things, despite - not because of - things at home.
I still teach in the same town, and some 20 years later I still see mum tottering along the high street, trying to catch sight of her reflection in the shop windows. It is not a pretty sight.
The writer is a former deputy headteacher. Send your worst parent stories to email@example.com and you could earn #163;50 in MS vouchers.