Should she marry a man who is a carrier of thelassaemia?
Question

                I would like to ask your opinion about a matter. A religious moral man has proposed to me, I am also moral and religious, I ask Allah to keep me this way. We were optimistic about this marriage. But by doing the pre-marriage examinations we found out that it is 50% possible that we will have children carrying thalassemia, 25% possible that we have healthy children, and 25% possible that we have children carrying thalassemia, because both of us carry this disease. Considering that if a person is carrier of this disease, it might be carried over to his children if he marries who carries the disease as well. While it is not the same case if he marries a healthy woman.   

My father has left the choice up to me. I am confused. Should I give preference to marrying a good man rather than to my children being healthy?.
Praise be to Allah.
    Firstly: 

    Undoubtedly one of the aims of marriage is to produce 
    righteous offspring and increase the numbers of the ummah of Muhammad  
    (peace and blessings of Allaah be upon him), as it says in the hadeeth 
    narrated by Abu Dawood (2050) from Ma’qil ibn Yasaar (may Allaah be pleased 
    with him) who said: A man came to the Prophet (peace and blessings of Allaah 
    be upon him) and said, “I have found a woman who is of good lineage and is 
    beautiful, but she does not bear children. Should I marry her?” He said, 
    “No.” Then he came again with the same question and he told him not to marry 
    her. Then he came a third time with the same question and he said: “Marry 
    those who are loving and fertile, for I will be proud of your great numbers 
    before the other nations.” Classed as saheeh by al-Albaani 
    in Irwa’ al-Ghaleel, 1784.  

    That also means producing offspring who are healthy and able 
    to do the duties enjoined by Islam, and to bear the burdens of conveying the 
    message. 

    If the couple know that their marriage may produce children 
    who are sick or who are carriers of a disease, then it is better for them 
    not to get married in that case, so as to ward off expected harm and to 
    reduce evil and harm in the ummah of Islam, and to protect themselves from 
    hardship and suffering that may affect them when taking care of a sick 
    child. 

    From what we have read, it seems that if both spouses are 
    carriers of this sickness, then each of their children has a 25% chance of 
    being healthy, a 25% chance of being affected, and a 50% chance of being a 
    carrier. But if one of them is healthy and the other is a carrier of the 
    disease, then the danger is greatly reduced, as the possibility of the child 
    being born healthy goes up to 50%, and the possibility of him being a 
    carrier of the disease is also 50%, but there is no possibility of the child 
    being born with the disease. 

    These possibilities are based on experience and research, but 
    the matter is entirely subject to the will and decree of Allaah. 

    As that is the case, then it is better for you to marry a 
    healthy person. This does not mean that you should put good health before 
    religious commitment as you say; what you have to do is to look for a 
    healthy man who is religiously committed, and there are many such, praise be 
    to Allaah. 

    If you give up the idea of this marriage for the sake of your 
    children, and to reduce the sickness and prevent it spreading further in the 
    ummah, then we hope that Allaah will compensate you with good, and reward 
    you for that. 

    We ask Allaah to help and guide you. 

    And Allaah knows best.