Is it necessary for husband and wife to
perform ghusl straight after love making or can ghusl be performed when they wake up in
the morning?

Praise be to Allaah.

It is permissible to delay ghusl until the time of Fajr
but it is mustahabb (recommended) for them to do wudoo’ before they sleep. This was
the view of the majority of scholars, and al-Nawawi reported that there was scholarly
consensus on this point. (al-Kaafi, 1/173; al-Muhadhdhab, 1/33; al-Mughni,
1/229)

Their evidence is the hadeeth of ‘Aa’ishah
(may Allaah be pleased with her) whose authenticity is agreed upon, in which she narrated
that when the Messenger of Allaah
(peace and blessings of Allaah be upon him) wanted to
sleep whilst he was in a state of impurity (junub), he would wash his private parts
and do wudoo’ as for prayer. (Narrated by al-Jamaa’ah).
They also use as evidence the report narrated by Ibn ‘Umar (may Allaah be pleased
with him) who said that ‘Umar said, “O Messenger of Allaah, may anyone of us
sleep when he is in a state of impurity?” He said, “yes, if he does
wudoo’.” (Agreed upon).

The wisdom behind doing wudoo’ is that it reduces
the impurity and is better for the body.

The Zaahiriyyah and Ibn Habeeb among the Maalikis thought that it was
obligatory for the person who is in a state of impurity to do wudoo’, on the basis of
the hadeeth of ‘Umar referred to above. And Allaah knows best.