They also see an inconsistency in authorities allowing up to 25 children in classrooms while banning large meetings of people or imposing curbs on nightlife in response to surging contagion.
In Madrid, those restrictions have been expanded even to private homes, where no gatherings of more than 10 relatives or friends are allowed.
Over 8 million students in Spain are beginning the academic year this week or next, with the starting date varying in each of its 17 regions and according to education levels.
Although scientists are still studying the role children play in spreading Covid-19, younger children appear less infectious than teenagers.
Children mostly suffer only mild infections when they catch the virus, but in rare cases they can get severe illness and studies have shown they can transmit Covid-19 to others in their households, including their parents.
Aroha Romero, a mother of two from the eastern region of Valencia, said the lack of clarity increases her anxiety.
“I would rather be threatened (to be charged with absenteeism) than have my children be motherless due to the coronavirus,” she said
Lorenzo Cotino, a law professor at the University of Valencia who has studied the impact of legislation in education, noted that schooling is widely supported in Spain since a 1970 law made physical attendance mandatory, reducing social divisions.
The pandemic has reinforced the idea that “equality and schooling go hand in hand", Cotino said, because "children in marginalized groups with less internet access received a poorer education at home”.