He did ‘umrah when he was junub because he did not know that it is obligatory to do ghusl
Question

                One of the brothers has asked me to look for an answer for him. He says: I entered ihram when I was fourteen years old, and it was the first ‘umrah for me after reaching puberty. I boarded the plane, then I fell asleep, and when I woke up I realised that I had had a wet dream and some of it got on my ihram (and I was ignorant at that time), and I did not pay any attention to that; I did not do ghusl and I completed my ‘umrah. A year or more later I began to realise what having a wet dream meant and that it is essential to purify oneself. I have not done ‘umrah again until now. Is my ‘umrah valid? Do I have to make it up – if it was invalid?
Praise be to Allah.
	Whoever 
	circumambulates the Ka‘bah in a state of janaabah, his tawaaf is invalid 
	according to the majority of scholars.

	It says in 
	al-Mawsoo‘ah al-Fiqhiyyah (16/52) – under the heading: What it is haraam 
	to do because of janaabah:

	It is also 
	haraam to do tawaaf (circumambulation of the Ka‘bah), whether it is 
	obligatory or supererogatory, because it is akin to prayer, as the Prophet 
	(blessings and peace of Allah be upon him) said: “Circumambulation around 
	the Ka‘bah is prayer, except that Allah has made it permissible for you to 
	talk during it.” The correct view is that its isnaad is mawqoof, ending with 
	Ibn ‘Abbaas. Therefore tawaaf is not valid on the part of one who is junub. 
	This is according to the Maalikis, Shaafa‘is and Hanbalis. But according to 
	the Hanafis, tawaaf done by someone who is junub is valid, but he has to 
	sacrifice a camel, because in their view being in a state of purity when 
	doing tawaaf is not a condition of tawaaf; rather it is waajib (obligatory). 
	And it is narrated from Ibn ‘Abbaas that he said: A camel must be sacrificed 
	during Hajj in two cases: if one circumambulates the Ka‘bah whilst in a 
	state of janaabah, and if he has intercourse with his wife after standing in 
	‘Arafah. End quote.

	Shaykh Muhammad 
	ibn ‘Uthaymeen (may Allah have mercy on him) was asked about someone who did 
	tawaaf al-ifaadah when he was junub and he replied:

	He has to repeat 
	tawaaf al-ifaaah, because he did tawaaf when he was in a state of janaabah, 
	and tawaaf is not valid if it is done when one is in a state of janaabah, 
	because the one who is in a state of janaabah is not allowed to stay in the 
	mosque, as Allah, may He be exalted, says (interpretation of the meaning):
	“Approach 
	not As-Salat (the prayer) … nor when you are in a state of Janaba, (i.e. in 
	a state of sexual impurity and have not yet taken a bath) except when 
	travelling on the road (without enough water, or just passing through a 
	mosque)” 
	[an-Nisa’ 4:43]. 
	If he is married, he has to avoid intimacy with his wife until he goes back 
	to Makkah and does tawaaf al-ifaadah. End quote.

	Majmoo‘ Fataawa 
	Ibn ‘Uthaymeen 
	(22/363, 364)

	Based on that, 
	your friend is still in a state of ihram for the ‘umrah for which he did 
	tawaaf when he was junub. Therefore he has to avoid the actions that are 
	prohibited when in ihram, and go to Makkah and do tawaaf and sa‘i, and cut 
	his hair or shave his head. Thus he will have completed his ‘umrah and 
	exited the ihram thereof.

	And Allah knows 
	best.