Question: Is there a yichud problem for a man and woman to be alone on…
Question: Reuven wants to go into his office on a Sunday to catch up on some work. He knows that the only other person there will be a female employee. To get around the problem of yichud, he plans on taking along his young son. Is this a good solution?
Answer: It depends how old the child is.
The halacha is that a child can serve as a shomer, guardian, to permit a man and woman to be together only if the child is old enough to realize what is going on around them and can relay to others what they have seen. [At the same time, if the child is a girl, she must also be young enough not to be tempted herself, or else she is just another woman. If she is the man’s daughter, then she can be a guardian even if she is older because a man may be secluded with his daughter without fear of sin.]
The Chazon Ish is quoted as saying that the minimum age for this would be six-years-old. Some Poskim say that girls became aware of what’s happening around them earlier than boys, so the age for a girl to be a guardian for another woman would be five years old. [Note, however, that Yichud is prohibited with one man and a young girl alone.]
Others say that there is no exact age and it depends on how mature the individual child is. Some say that a girl reaches this level of maturity when she feels embarrassed to be undressed in front of others. I believe that the accepted ruling is that a boy can be a shomer from the age of 6, and a girl from the age of 5.