{"id":1099,"date":"2026-05-17T18:25:00","date_gmt":"2026-05-17T17:25:00","guid":{"rendered":"https:\/\/www.farmersforum.ie\/trends\/above-20c-pregnancies-yield-fewer-boys-according-to-a-large-university-of-oxford-study\/"},"modified":"2026-05-17T18:25:02","modified_gmt":"2026-05-17T17:25:02","slug":"above-20c-pregnancies-yield-fewer-boys-according-to-a-large-university-of-oxford-study","status":"publish","type":"post","link":"https:\/\/www.farmersforum.ie\/trends\/above-20c-pregnancies-yield-fewer-boys-according-to-a-large-university-of-oxford-study\/","title":{"rendered":"Above 20\u00b0C, pregnancies yield fewer boys, according to a large University of Oxford study."},"content":{"rendered":"<p><strong>An Oxford University study analyzing more than five million births reveals a troubling phenomenon: when temperatures rise above 20\u00b0C, pregnancies are less likely to result in boys. A finding that suggests global warming could alter our future.<\/strong><\/p>\n<figure class=\"wp-block-image size-large\"><\/figure>\n<h2 class=\"wp-block-heading\">Millions of births analyzed reveal a direct impact of extreme heat<\/h2>\n<p>At first glance, a baby\u2019s sex might seem like a well-tuned biological lottery. In most populations, slightly more boys are born than girls. Yet by delving into <strong>more than five million births<\/strong>, Oxford University researchers observed a variation too pronounced to ignore.<\/p>\n<section class=\"incontent-related\"><span class=\"incontent-related__title\">Read also<\/span> <span class=\"incontent-related__desc\">In Seoul, connected trash bins charge per kilo dumped and reveal the limits of rewarded sorting in dense cities<\/span><\/section>\n<p>Their study, published in the journal <strong>PNAS<\/strong>, draws on data from 33 countries in Sub-Saharan Africa and India. When temperatures rise <strong>beyond 20\u00b0C<\/strong>, the male-to-birth ratio declines. In other words, pregnancies exposed to significant heat are less likely to result in the birth of a boy.<\/p>\n<p>This isn\u2019t science fiction, nor a climate prophecy dressed up to scare. It\u2019s a subtle statistical signal, buried in birth records and weather observations. A detail almost invisible, but one that becomes more worrying as <strong>heat waves<\/strong> spread.<\/p>\n<h2 class=\"wp-block-heading\">Male fetuses appear more vulnerable to thermal stress during pregnancy<\/h2>\n<p>The most troubling aspect of the study concerns the vulnerability of male fetuses. The researchers suspect that <strong>maternal thermal stress<\/strong> weighs more heavily on their survival before birth. The pregnant body, already mobilized by a complex physiology, must then manage an additional constraint.<\/p>\n<section class=\"incontent-related\"><span class=\"incontent-related__title\">Read also<\/span> <span class=\"incontent-related__desc\">This unexpected climate paradox suggests the preindustrial atmosphere was less \u201cpure\u201d than believed<\/span><\/section>\n<p>In Sub-Saharan Africa, the effect is most marked during the first trimester. It is a pivotal period, barely visible from the outside, when decisive developmental steps are set in motion. Excessive heat could raise prenatal losses, with a stronger impact on <strong>male embryos<\/strong>.<\/p>\n<h2 class=\"wp-block-heading\">In India, extreme temperatures also influence family behaviors<\/h2>\n<p>The Indian case adds an unexpected layer to the story. The country has long shown a gender imbalance, linked notably to a cultural preference for sons and to <strong>selective abortion practices<\/strong>. In this context, heat does not produce only a biological effect.<\/p>\n<p>According to the researchers, episodes of extreme temperatures could also disrupt access to clinics, travel, or certain family decisions. During the second trimester, this temporary disruption appears to coincide with a <strong>drop in male births<\/strong>. Climate then enters a more intimate territory: that of human behavior.<\/p>\n<section class=\"incontent-related\"><span class=\"incontent-related__title\">Read also<\/span> <span class=\"incontent-related__desc\">The Panama Gulf saw the disappearance of its cold-water upwelling, a quiet driver of fish, corals, and coastal incomes<\/span><\/section>\n<p>This detour through India serves as a reminder that birth statistics are never merely columns in a table. They carry habits, economic constraints, and sometimes deeply rooted family pressures. When <strong>extreme heat<\/strong> joins this mix, it can shift the balance in ways that are hard to predict.<\/p>\n<h2 class=\"wp-block-heading\">Climate change could permanently reshape the demographic balance<\/h2>\n<p>Climate change is often framed by fires, droughts, or rising seas. This study forces a shift in focus toward something quieter: <strong>life before birth<\/strong>. The climate no longer acts only around us; it could already influence who comes into the world.<\/p>\n<p>The implications are substantial. A lasting change in the girl-to-boy birth ratio could affect demographics, families, and health systems. Nothing guarantees these effects will be uniform, but the study shows that <strong>each additional degree<\/strong> can yield unforeseen consequences.<\/p>\n<section class=\"incontent-related\"><span class=\"incontent-related__title\">Read also<\/span> <span class=\"incontent-related__desc\">Deprived of gas cylinders, Indian farmers turn to cow dung for daily cooking<\/span><\/section>\n<p>The question now extends beyond mere scientific curiosity. Protecting pregnant women from heat, <strong>improving access to care<\/strong>, and adapting housing becomes a public health issue. In a warmer world, demographics could be shaped even in the shadow of thermometers.<\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":1100,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[1403,1406,1407,1409,1404,228,1408,1405],"class_list":["post-1099","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-20c","tag-boys","tag-large","tag-oxford","tag-pregnancies","tag-study","tag-university","tag-yield","generate-columns","tablet-grid-50","mobile-grid-100","grid-parent","grid-50"],"_links":{"self":[{"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/posts\/1099","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/comments?post=1099"}],"version-history":[{"count":1,"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/posts\/1099\/revisions"}],"predecessor-version":[{"id":1101,"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/posts\/1099\/revisions\/1101"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/media\/1100"}],"wp:attachment":[{"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/media?parent=1099"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/categories?post=1099"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.farmersforum.ie\/trends\/wp-json\/wp\/v2\/tags?post=1099"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}