Fathwa, - Can I have my sister-in-law nurse my son without my husband's consent

Question:
My question is regarding whether I can have my sister-in-law nurse my
15 month old son so that he would become her and her daughter's
mahram. The complication is that my husband finds this idea really
strange and for no valid reason is saying no but I have a very good
reason for wanting to do this. Once he is older, I want to be able to
easily let him visit my brother's house and not have them worry about
him not being their mahram. We go there a lot because our kids play
and I don't like to be in the un-Islamic environment of my in-laws
house. I don't want to have my son go to my husband's family's house
too much because they listen to music, have mixed gatherings and watch
movies all day. So I would really appreciate it if you would let me
know whether I can still go ahead and have my sister in law nurse my
son without my husbands consent.
Answer:
It is the principle of Shariah that the mother of a child is morally
responsible to breastfeed her child, as Allah Most High says:
"The mothers shall breastfeed their offspring for two whole
years."(Surah al-Baqarah, 233)
As such, it is the moral responsibility of the mother (in normal
cases) to breastfeed her child and not have it suckled by another
woman.
However, if there is a genuine reason for her not doing so, then she
can get her child suckled by another woman. Allah Most High says:
"If you decide on a foster-mother for your offspring, there is no
blame on you, provided you pay (the mother) what you offered, on
equitable terms."(Surah al-Baqarah, 233)
In the above verse, Allah Most High addressed both the parents using
the Arabic term of addressing a group (aradtum), thus deciding on
getting the child suckled by another woman will be the domain of both
the mother and father. It will be something that is jointly agreed
upon and not based solely on the decision of one parent.
However, if the mother is not able to breastfeed her child, then the
husband cannot force her in doing so.
Imam al-Mawsili (Allah have mercy on him) states:
"It is not necessary upon the mother to breastfeed her child…unless
she becomes appointed for it, such as when the husband cannot find
anyone else or the child refuses to take the milk of another woman. In
such a case, it will become binding on her, in order to save the child
from perishing. (In the situation where the mother refuses to
breastfeed), the husband will be responsible for hiring a wet nurse
for the child, for the responsibility of paying for the wet-nurse lies
on the husband and the responsibility of breastfeeding on the wife. It
will not be permissible for the husband to hire his own wife (m: the
child's mother) to breastfeed the child, for breastfeeding is
originally her responsibility, due to the statement of Allah Most High
"The mothers shall breastfeed their offspring for two whole years".
Thus, when the mother refuses to breastfeed, we would consider that to
be due to a genuine reason (udhr) but when she is prepared to
breastfeed the child on hire, we found out that she is in reality
capable of breastfeeding her child, thus it will become binding on
her. Therefore, it will not be permissible for her to take money on
something that is binding (wajib) on her."(al-Ikhtiyar li Ta'lil
al-Mukhtar, 3/230-231)
Another great Hanafi jurist (faqih), Imam al-Haskafi (Allah have mercy
on him) states:
"It is not permissible for the father (m: of the child) to force his
free (i.e. not a slave) wife to breastfeed the child, even before the
two years have elapsed, for the right of upbringing the child is of
the mother."(See: Radd al-Muhtar ala al-Durr al-Mukhtar, 3/211-212)
In view of the above, it becomes evident that although primarily the
responsibility of breastfeeding the child is of the mother, but if she
is incapable due to some reason, she may hire someone else to
breastfeed the child.
With regards to your situation, you intend to have your child
breastfed by your sister in-law for (I presume) a short period of time
or just as a one off thing, so that the rules of fosterage (radha'ah)
are established.
In such a case, although I could not find a explicit text in the books
of Fiqh, it seems that you should do this with the consent of your
husband, as Allah Most High addressed both the parents in the verse
quoted above that if you decide on a foster-mother for your offspring,
there is no blame on you.
Moreover, Allah Most High says in the same verse quoted earlier:
"No mother shall be treated unfairly on account of her child. Nor
father on account of his child."(al-Baqarah, v. 233)
The meaning of this verse is that none of the respective parents
should be harmed with regards to the breastfeeding of the child. The
verse is specific to certain aspects but in a general manner applies
to all aspects relating to harming any of the parents with regards to
the breastfeeding of the child.
You should also remember that, when the rules of fosterage (radha'ah)
are established, then along with the rules of Hijab being lifted, your
son will not be able to marry your brother's daughter in the future.
Thus, you need to be very careful in taking this step, for it can
prove to be difficult in the future.
Moreover, scholars mention that even in the case where one has a
foster relationship, if there is a fear on Fitna, it will be necessary
to observe Hijab, and remaining in privacy (khalwa) will not be
permissible.
In conclusion, both you and your husband must sit and decide on this.
Weigh the pros and cons in getting you son breastfed by your brother's
wife, and then decide. It will be something that is jointly agreed
upon by both of you.
And Allah knows best.