On delaying the marriage of a young woman until completion of high school or university education.

Question:
There is a widespread custom of a young woman or her father refusing those who propose to her until she has completed her high school or university education, or so that she may study for a number of years. What is the ruling on that? And what is your advice to those who do so, so that the young women might reach the age of thirty or more without marrying?
Answer:
My advice to all young men and women is to marry without delay and to hasten to it, if conditions permit, as the Prophet sallallaahu alayhi was salaam said: ‘O you young men! Those among you who have the means and the ability should marry, because it restrains the eyes (from evil glances) and preserves the private parts (from immorality). And whoever is unable to do so, should fast because it is a protection for him.’ (Al-Bukhari no. 5066 and Muslim no. 1400) And he sallallaahu alayhi was salaam said: ‘If one whose religion and character pleases you proposes to you, then marry (your daughter to) him. If you do not do so, it will be a cause of trial in the land and great corruption.’ (At-Tirmithi no. 1084) Narrated by At-Tirmithi with a Hasan chain of narrators. And he sallallaahu alayhi was salaam said: ‘Marry productive, loving women, because I will have the largest number of followers on the Day of Resurrection.’ (Abu Dawud no. 2050, An-Nasa'i no. 3229, Ahmad 3/158, 245 & Ibn Hibban no. 4028) Narrated by Imaam Ahmad and authenticated by Ibn Hibban. It is also necessary due to the many benefits indicated by the Prophet sallallaahu alayhi was salaam, such as averting one’s gaze, protecting the private parts (from sin), increasing the size of the Muslim community, and safety from great corruption and evil consequences. May Allaah grant all of the Muslims success in attaining that wherein lies righteousness in the matter of their religion and their earthly life. Verily, He is All-Hearing,
Near. Shaykh `Abdul-`Azeez Bin Baz
Fatawa Islamiyyah, Darussalam, volume 5, pages 174/175
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The ruling on a Women Studying Engineering or Chemistry
Question:
Can a girl pursue studies in the sciences, in fields such as Chemistry, Physics, etc?
Answer:
A women should not specialize in a field that is outside of her realm. She has the opportunity to pursue many fields that are suitable to her, like Islamic Studies or the Arabic Language. Fields such as Chemistry, Engineering, Architecture, Astronomy and Geography do not suit her. A women should choose what benefits her and that which benefits society. Furthermore, men need to establish institutions for women that will prepare them for those fields that they need to study, Gynecology and pre-natal care being important examples.
Shaykh `Abdul-`Azeez Bin Baz Fatawa Islamiyah vol.8, p.128, DARUSSALAM
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The Ruling on Mixing With Women With the Claim of Having a Blameless Intention
Question:
We have a bad custom, which is the mixing of men with women. The reason is that we work with them in many occupations and look at them, and they do their work without their faces being veiled. We say that our intention is blameless, so someone of us will look at the face of his full brother's wife and he considers her to be like his full sister, whom he is unable to marry, and he considers the wives of his neighbours to be in the same position as women he cannot marry. A man in our society lives with his full brother and his uncle's son, and other members of his family with the men and women eating and drinking together. What is the ruling?
Answer:
These matters belong to the customs of the first Jahiliyyah (the days of ignorance, prior to the start of the mission of Prophet Muhammad sallallaahu alaihi wasallam) and it is an obligation, according to Islamic Law, for the woman not to uncover her face except to those who are Mahrams for her. Similarly, it is an obligation upon a woman not to mix with men who are unrelated to her when she is unveiled, and it is also incumbent upon her not to be secluded in any place with a man to whom she is unrelated - that is, one who is not a Mahram for her. There is no doubt that mixing of men and women in the manner which you have described is in contradiction to the Islamic Law, because it causes an infinite amount of corruption. And Allaah is the Granter of success.
Shaykh `Abdul-`Azeez Bin Baz Fatawa Islamiyah, Darussalam, volume 5, page 137