DISCLOSING ONE'S DEFECT BEFORE MARRIAGE

A defect is something either medical in nature , mental and/or physical defect which others may not like


(روى أبو عبيد بإسناده عن سليمان بن يسار أن ابن سند " كذا، وصوابه ابن سندر" تزوج امرأة وهو خصي، فقال له عمر: أعلمتها؟ قال: لا، قال: أعلمها، ثم خيرها)

Abu Ubayd narrated through his own chain from Sulaymaan bin Yasaar: “Ibn Sanad married a woman while he was castrated. Umar asked him, „Did you tell her?‟ He said, "No‟. He (Umar) said, "Tell her and then give her choice (to live with you or not).” 

[Ref: Ibn abi shaybah 2/70/7 . Shaykh saleh has brought the complete chain and pointed towards its correctness in at-takmeel] 

In another narration attributed to `Umar (r.a)., `uthman ibn affan (r.a) , Mugheera ibn Shu`bah (r.a) and Ibn Mas`ood (r.a) 

أن العنين يؤجل سنة ".

an impotent (who realised his impotency later on) will get one year for treatment (after which the woman is entitled to be divorced) 

Here in the GCC kingdoms, before marriage an entire medical and physiological exam is done of spouses and reports handed over the respective families by the govt administration. There is nothing to be ashamed of in this even if you happen to have one/more defects (big or small) as it is the right of either side to know beforehand. 

This is the beauty of Islam. It encourages justice and not modern day feminism/absolute equality.