What will be the effects of marrying my cousin?

Absolutely there should not be any problem. She is your father's cousin sister's daughter. I don't foresee any issued. My son married my cousin sister's daughter only. Both of them are happy. They have a baby girl. Everything is fine with them. My sister married my mother's cousin brother. In that case, also there are no problems. They are also happy. They have one daughter and one son. All are doing well. If you want, you get the blood groups verified. If they are not the same, you will not have any problem.
You can marry her.

A.Is this type of marriage accepted?
In India, especially South India, it is common for a man to marry his father's sisters daughter or mother's brother's son or daughter. The problem comes when the cousins come from father's brother's children or mother's sister's children. There should not be an issue for you as your situation would be accepted.

B.Can there be any medical issues for the next generation?
This would be a valid point that needs professional to advise. First, make a family tree from your side and the girl's side going back at least 4-5 generations. Make a note of the diseases, birth defects, stillbirths, members with extra toes or fingers, low intelligence etc. Basically, the medical specialist will look at this marriage between close relatives as Consanguineous marriage and try to predict potential congenital diseases that can be passed on by you both to your children in the future.
There are many hospitals in the corporate/private sector and the major teaching medical colleges and premier government hospitals that offer Pre-marriage Genetic screening and counseling for closely related people about to get married.

Can this marriage affect us?
Once you attend a couple of consultations with the experts, they would check for the potential risk of abnormalities with vision, hearing, mental development and certain blood disorders.If there is no serious risk of passing down diseases, then you need not worry. Both of you love each other and have a harmonious life ahead.

The advice to you would be, keep an open mind, the problems are more when it is a first-degree cousin etc, so meet the genetic counsellors in your area and then go forward with your marriage and life.

You can also read these simple brochures for some more details.
https://www.bradford.gov.uk/media/3276/cousin-marriage-and-genetic-inheritance-leaflet.pdf
http://geneticsaware.group.shef.ac.uk/html/hcp/furtherresources/EnglishbookletfinalSheffieldversion.pdf

Is this type of marriage accepted?
Whether you can marry your cousin or not depends on your religion and culture. Muslims can freely marry their cousin. However, Hindus as per Hindu Marriage Act of 1955 cannot marry their cousins. As per this act, cousin marriage is illegal in Hindu religion. An exception is given to regional customs. In the North part of India, it is considered as incest. In South India, cousin marriage is common. In Southern India and Maharashtra, only those individuals can marry their cousins whose customs allow them to do so. It is legal only if custom related to certain communities give permission. Otherwise, it is considered an illegal act. Since you have not specified regarding your culture and caste and from the area from where you belong, it's difficult to answer your question. Special Marriage Act, however, allows marriage between second cousins.

Can there be any medical issues for the next generation?
It has been reported that babies who take birth out of such weddings suffer from congenital disorders. Heart abnormalities followed by disorders in the nervous system, limbs, and other organs top the list. Chances of abnormalities increase as there is a risk that child may inherit the two sets of faulty genes. When the marriage takes place outside the family in the wider community, parents tend to bring genes from a large pool. The chances of faulty genes decrease. However, most of the kids are born normal. Only 3% suffer from medical issues.

Will this marriage affect us?
If your custom and religion allow you to marry your cousin, only then get married. Don't do anything illegal. Seek the help of a good lawyer and sort out things. You can even take police protection if you feel that someone might physically threaten or harm you in any way. Apart from legal issues, you may have to face rigidity and resistance of your family members.

There have been much medical research on the subject of consanguineous marriages and it is understood that hereditary diseases have more probability of recurrence in the future generations in such cases. Due to this reason some people are apprehensive of these negotiations.

Anyway, in some communities such marriages are very common and they do not consider it harmful.

Another aspect is social acceptability. In some communities it is not considered as a good proposition and then the people going for such match might be having a problem of acceptability in their close relation circle.

One should go for consanguineous marriage only after considering the above aspects.

The marriage in near relation has been always a matter of much discussion as it is treated separately in different societies.

There are doubts regarding culmination of hereditary diseases also. So some people are very cautious about these.

One thing which can be done is go for medical tests (like blood tests etc) and consult an expert doctor regarding compatibility. There are certain tests which give directions in this regard and accordingly one can take the appropriate decision.

You must follow the practices of law. According to Hindu - marriage act 1955, there are details of the provisions where such marriages are forebidden. But there are many considerations where such marriages are legalised especially in the south - India where there is no such restrictions in observance of such marriages. However, you need to think over some of the pertinent points before you enter into such a permanent contract. A few points to be contemplated are as follows-
1) Both of you should have clear understandings of diverse Hindu - cultures and a clarity of mind at all stages is essential to enjoy a happy matrimony.
2) Both of you should respect the emotions of each other and should have a great degree of reliance in all the circumstances. Both of you should have an excellent sacrificing attitude in the hours of crisis.
3) Both of you should enjoy excellent financial - status so that the family expenses are met successfully especially when both of you enjoy the parenthood - stage.
4) Both of you should be eccellent planners to make your kids responsible, educated and sensible citizens by providing right environments.
5) Both of you should be practical by not being over sentimental with the irresponsible comments made by your neighbours.
6) Both of can undergo for RH blood test in order to ascertain any complications arising out of pregnancy and should have consultation with a competent doctor to dilute such effects.

All marriages are to be considered problematic if no cordial understanding lapse between couples. In this case as mentioned by you, the understanding between your family members and the girl opted by you is believed as cordial relationship /understanding will be positive as she is a relative and know well about the family members. Mainly the misunderstanding comes in families because the new comer do not understand or follow the customs of the husband's side and the insisting by elders will irritate her. So, go ahead, is my suggestion.

You are good to go. Genetically there is no issue. But if you want you can check her heredity if they have any family problems. Usually your DNA should not match with your spouse which can carry problems. With that said you must know now you don't see any problems. It is also good to have Rh of blood of same type. This can cause issue for birth but nowadays well precautions available. Right now don't think too much and settle down.

Is this type of marriage accepted?

In North India such marriages are normally not acceptable but in South India such marriages are very normal. As people think its easy for the couple to adjust with the family as they know family of each others before the marriage.

Will there be any medical issues for the next generation?

I don't see any problem with it if your parents are agree for the same. There would have been a problem had she been your first cousin. It is observed in such marriages there are chances that the babies of the couple may have genetic disorders specially when the parents have some harmful genes.

Can this marriage affect us?

It may affect if your society doesn't permit such marriages. People will talk about you at your back. But that's temporary people will forget it after some time.

1. There is no legal bar in such marriages among distant relatives in India.
2. However, in north India including West Bengal, such marriages are not preferred.
3. In south India, such marriages are very common.
4. However, I do not know the position in Marathi society (I presume that you are Marathi).
5. There is always a chance of genetical defect/deformity in case of marriage between relatives, but a qualified physician can inform you more on this issue. Please consult a physician (preferably haematologist) and get your (both of you) blood test done before taking the final decision regarding marriage.