He has Klinefelter syndrome; does he have to wear hijab?

Klinefelter syndrome is a condition that affects males
because of irregularities in the chromosomes. It is named after Dr Henry
Klinefelter, who first described it in 1942 CE. 

Symptoms include: 

1.Sterility, as a result of the
lack of cells that produce sperm.

2.Larger breasts.

3.Weak muscles, like those of a
woman.

4.Pubic hair may resemble that of
the female.

5.Impotence and low sex drive.

6.Small testicles.

Individuals who are affected by this condition are males, and
the rulings concerning males – particularly with regard to interactions with
women – also apply to them; so it is haraam for them to mix with women, look
at them, imitate them and other rulings governing interactions of men with
women. 

They may seek treatment for this disease, and there is no sin
on them and no shar ‘i blame for having physical features that resemble
those of females. But they also have to avoid resembling women in their tone
of voice, movements, clothing and so on, because for men to imitate or
resemble women is a major sin, as we have explained in fatwa no.
81994

With regard to hijab, he does not have to wear hijab, because
he is a man and hijab is only for women, not men. But we should point out an
important matter, which is that if he is afraid in a particular situation
that he may be a source of temptation for people, then he must avoid that
situation. The same applies to anyone who fears that he may be tempted if he
mixes with a person who has this condition; he should avoid interacting with
him and he should lower his gaze and avoid looking at him, especially if
that person is good-looking. In that case he comes under the same ruling as
the ruling on “beardless youths,” in whose case there may be the fear of
temptation. 

For rulings on interactions with beardless youths, please see
fatwas no. 178152 and
94836 

And Allah knows best.