There is no basis for that. What has been narrated from some about the testimony of a children’s teacher not being acceptable is to be rejected. Teaching is something honourable, which raises a person in status. The one who teaches people and guides them to good – the Lord, may He be exalted, the angels and even the ant in its hole and the fish in the sea, send blessings upon him. This is stated in a hadeeth narrated by al-Tirmidhi and classed as saheeh by Shaykh al-Albaani in Saheeh al-Jaami’ (4213).
The wording of the hadeeth is: “Allaah and His angels and the inhabitants of the heavens and the earths, even the ant in its hole and the fish in the sea send blessings upon the one who teaches people what is good.” Narrated by al-Tirmidhi (2685).
Ibn Hajar al-Haytami (may Allaah have mercy on him) was asked:
I saw a quotation from al-Khulaasah which said: “The testimony of a children’s teacher is not to be accepted, for the minds of eighty teachers are not equivalent to the mind of one woman.” Is this sound and proven or not? What is the ruling on this issue?
I looked for this text in al-Khulaasah by al-Ghazaali and I could not find it there. I do not think it is in the books of any of our companions, because it is more akin to nonsense. How many teachers of children have we seen by whose virtue rain was sought because they attained a high level of integrity, chastity, justice and righteousness. If these words are proven to be narrated from a scholar, then they should be understood as referring to a specific teacher in whom there are signs of ignorance, wrongdoing or insanity, as is the case nowadays among those who undertake this profession, which is the noblest of professions according to the statement of the Prophet SAWS (peace and blessings of Allaah be upon him). And Allaah knows best.
Al-Fataawa al-Fiqhiyyah al-Kubra (4/358)
And Allaah knows best.