Answer: The little squash that are aborting have not been pollinated. A squash plant develops both male and female blossoms. The pollen has to be transferred from the male flowers to the female flowers (usually by visiting bees). When pollen is transferred, the squash will develop. If it is not transferred, the squash will grow a couple of inches and then die off. The only way to ensure good pollination is to encourage bees and wasps by avoiding the use of pesticides and by planting other colorful flowers in your garden. The season is long so I expect you'll get lots of squashes later this summer.
Best wishes with your garden!
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