Pride month says “love is love”. So why ban marriage between cousins?

Familiar slogans are once again appearing across social media feeds, corporate advertising campaigns and rainbow-coloured window displays. For years, perhaps the most influential slogan associated with Pride Month has been the simple phrase: “Love is love.”

The message is straightforward. If two consenting adults love one another, why should anyone else stand in their way?

During the debates over same-sex marriage, many Christians who raised concerns about redefining marriage were told that opposition could only stem from prejudice or irrational discomfort. 

Marriage, we were assured, was simply about love and commitment between consenting adults of whatever sex. The state had no business imposing moral boundaries on private relationships. “Some people are gay – get over it!” another punchy Stonewall campaign caption read. 

Yet a curious debate has emerged across Europe. 

The limits of “Love is love”

Last week, Sweden voted to ban marriage between first cousins. Similar proposals have been circulating in Westminster. Strangely, these ideas have been put forward by politicians who have long supported same-sex marriage and other liberal reforms (see, for example, the voting record of Richard Holden MP, the parliamentarian who has been campaigning to bring a ban to the UK).

For a child to lack a mother or a father is a tragedy. To deliberately deprive them of one under the banner of “progress” is truly cruel

The question is difficult to ignore: if we should celebrate marriages between any two adults who love each other and consent, who’s to draw the line at relatives? 

“Some people fancy their cousin – get over it!”, to borrow a phrase. 

Of course, there are serious arguments put forward against this practice. Genetic risks are often cited, and those concerns should not be dismissed lightly. Children born to first-cousin couples face a slightly increased risk of having a disability or a deformity. 

But genetics alone cannot fully explain the debate.

After all, a marriage ban does not technically prevent cousins from having children. Nor does marriage guarantee that a couple will have children. In Britain, almost half of children are born outside of marriage altogether. If the primary concern is reducing the number of children born to first-cousin couples, banning marriage seems an indirect solution. 

Furthermore, we do not generally prohibit marriage because prospective parents face elevated risks of passing on medical conditions. Women who have children later in life face significantly increased risks of certain chromosomal abnormalities compared to younger mothers.

In fact, children born from “geriatric” pregnancies carry a higher overall likelihood of having a disability or deformity than children born to parent-cousins in their 20s. Yet nobody proposes banning women over 40 from marrying or becoming parents. Nor should they.

And this is where the cousin-marriage debate becomes so revealing. Even if a pair of first cousins had no intention of, or ability to have children, many people would still feel uneasy about their marriage. In Gen Z parlance, it simply gives them “the ick”. The reaction is not merely about statistics or genetics – there’s an instinctive moral line being crossed.

In other words, almost everyone believes there are boundaries after all. 

Christians need not be embarrassed by the belief that marriage has a God-given shape and purpose.

Despite what they may say at Pride marches, human beings do not actually live as though all relationships are morally equivalent. We make judgements all the time about family life, sexuality and the common good. We recognise that some relationships should be encouraged and celebrated, while others should not. The disagreement is rarely about whether boundaries exist; it is about where those boundaries should be drawn. 

Marriage’s God-given design

The Bible’s vision for marriage has never been arbitrary. Men and women are distinct beings, each with a different emphasis in reflecting the nature of God; each bringing complementary strengths and weaknesses into a union designed to mirror, however imperfectly, His love for His bride, the Church. 

From Genesis onwards, marriage is presented as a covenant between a man and a woman that creates a new family unit and provides a stable environment for raising children. Scripture places boundaries around marriage, not because God delights in restriction, but because He designed marriage for a particular purpose. 

Indeed, the Bible’s prohibitions on close-kin sexual relationships long predate modern concerns about genetics – and extends even to close non-biologically-relatives (step-sisters, sisters-in-law, daughters-in-law etc.). The issue was not primarily scientific but moral and social. Family relationships were to be of a protective nature, not a sexual one. Those boundaries allowed for social cohesion in family units, and condemned intra-family sexual abuse. 

God’s commands reflected an understanding of human flourishing that extended beyond individual desires. There are lines that must not be crossed.

Marriage has always been about more than the feelings of adults. It has implications for families, communities, and perhaps most of all – children. 

More than two individuals

The same logic is applied when it comes to objections of two males, or two females, forming a new family unit. In recent years, surrogacy and other reproductive technologies have been promoted as a means to overcome biological reality and force new family structures into existence. But while the fulfilment of adult desire to parent might be intuitively celebrated, the impact on children is troubling.

Kids need both a mum and a dad. Newborn babies reach for the soothing and comfort of the mother they knew in the womb. Separation from her at birth is documented to have a troubling psychological impact on an infant both at the time, and in the years to come. Meanwhile, the damage caused by absent fathers – and the greater likelihood of children without dads to drop out of education, engage early in sexual relationships, and even end up in prison – is common knowledge, highlighted even by Barack Obama.

For a child to lack a mother or a father is a tragedy. To deliberately deprive them of one under the banner of “progress” is truly cruel. 

The renewed debate over cousin marriage therefore reveals something important about our culture. Despite decades of rhetoric suggesting that marriage is simply about consenting adults, society continues to recognise that marriage serves purposes beyond individual fulfilment. 

Christians need not be embarrassed by the belief that marriage has a God-given shape and purpose. Modern culture often assumes that freedom means the absence of boundaries. Christianity offers a different perspective. True freedom is found not in doing whatever we desire, but in living according to the design of the One who made us. God’s boundaries are not arbitrary barriers to happiness; they are guardrails intended for our good.