Answer
Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Physical deformation, which may affect the relation between spouses, must be disclosed before marriage. Yet, simple defects that may not affect the relation between them, neither physically nor psychologically, need not be disclosed, though sometimes keeping the other party informed about them will be better, in order not to leave a room for suspicions.
Elaborating on this issue, Dr. Abdul Fattah `Ashoor, Professor of the Exegesis of the Qur’an at Al-Azhar University, states:
Asma’ bint Abu Bakr (may Allah be pleased with her) reported that a woman asked the Prophet (peace and blessings be upon him), “O Allah’s Messenger! My daughter was infected with measles that caused her hair to fall. Now that I’m giving her in marriage, can I adjust her hair with artificial braids?” Then the Prophet replied, “Allah has cursed the lady who adds artificial hair (to her or to someone else’s) (al-wasilah) and also the one who asks for it (al-austawsilah).” (Muslim)
This hadith is taken as clear evidence on the necessity of telling the suitor about any defects, because he may not be satisfied with a lady with a fallen hair, and hiding such defects amounts to an act of deception.
But if he is informed of the issue before marriage, he will have the option either to go ahead with that or not.
So, regarding your case, if the birthmark in the leg is the kind of defect that is likely to affect the relation between the parties to the marriage contract, then it must be revealed. But if it is a simple thing that does not deface the leg, there is nothing wrong that.
Shedding more light on the issue, Dr. `Abdul Fattah Idrees, Professor of Comparative Jurisprudence at Al-Azhar University, adds:
If a lady suffers from any disease, she has to inform her suitor of it, because on knowing about her disease, the suitor may refrain from marrying her.
So the Prophet urged frankness between a lady and her suitor. It is reported that Al-Mughirah ibn Shu`bah (may Allah be pleased with him) proposed to a woman from Al-Ansar (the Helpers). The Prophet asked if he had seen her. The man told him that he hadn’t. Hence the Prophet said to him, “Go and see her, because Al-Ansar have some defect in their eyes.” (An-Nasa’i) Some scholars refer to this defect as weak-sightedness.
Therefore, a suitor should be informed of any diseases, whether hereditary or not, infecting the lady he is proposing to. The other way round, a lady should also be informed of the same things in her suitor. This is to evade the bad consequences of knowing this after marriage, for this may cause nullification of marriage contracts.
Almighty Allah knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.