Modes Of Avoiding Irregular Marriage
Following are the modes of avoiding irregular marriage.
i By the court
The court can cancel the marriage if the matter is brought to its notice.
ii By husband
The husband can repudiate his wife.
iii By wife
The wife can also avoid the marriage by relinquishment.

Examples:
i A marriage without witnesses.
ii A marriage with a woman observing Iddat.
iii A marriage prohibited on ground of difference of religion.
iv A marriage with two sisters at the same time.
v A marriage to a fifth wife

Legal Effects Of A Valid Marriage
Following are the legal effects of valid marriage.
i The sexual intercourse becomes lawful.
ii Mutual rights of inheritance are established.
iii The children born out of the wedlock are legitimate.
iv The wife becomes entitled for maintenance.
v The wife becomes entitled to Dower.
vi Neither of the spouses acquires any interest in property of the other by reason of marriage.
vii The wife has to observe the Iddat in case of death of herhusband or in case of divorce.
The rules of affinity come into operation in case of valid marriage.
Examples:
i A marriage without witnesses
ii A marriage with a woman observing Iddat.
iii A marriage prohibited on ground of difference of religion.

14. Legal Effects Of A Void Marriage
Following are the legal effects of valid marriage.
i The sexual intercourse becomes unlawful.
ii The void marriage creates no right and obligation upon any party.
iii The children born out of the wedlock are illegitimate.
iv The wife does not become entitled for maintenance and inheritance.

Miscellaneous Prohibitions: 
The Doctrine of Equality in Marriage (Kafa’a)
The Holy Prophet(PBUH) is reported to have recommended marriage with fit spouses:’ Marry your equals’. The Hanafis hold that equality (Kafa’a) between the two parties is a necessary condition in marriage. The following factors must be considered for determining equality:
i Family
ii Islam
iii Profession
iv Freedom
v Good Character
vi Means
18. Conclusion:
In short, marriage is not a sacrament but a civil contract between two persons of opposite sex. Every Muslim of sound mind and has attained age of puberty may enter into contract of marriage.