This is a copy of a chat between Claude and user. Content may include unverified or unsafe content that do not represent the views of Anthropic. Shared snapshot may contain attachments and data not displayed here.
What is the paternal vs maternal contribution to birth defects and congenital diseases from age 20s vs 50s, each controlled for paternal and maternal age. use absolute risk numbers. separate the diseases by reproductively continuable (like ADHD or bipolar) vs reproductively uncontinuable (like stillbirth, miscarriage, or down syndrome) show the results in a easy to read compact table
Here's a synthesized view from the epidemiological literature. Important upfront caveats: maternal age 50 conceptions are extremely rare without donor eggs (which strips the chromosomal-error contribution), and "controlled for" the other parent means the effect is independent of that parent's age but residual confounding (smoking, BMI, parity, IVF) is hard to fully eliminate.
(pregnancy loss, early death, or conditions that preclude reproduction)
| Outcome | Mother 20s | Mother 50s† | Father 20s | Father 50s |
|---|---|---|---|---|
| Clinically recognized miscarriage | ~10% (low at 25–29) | ~50–75%+ (own eggs) | reference | ~14% (≈1.4× of 20s) |
| Stillbirth (per 1,000 births) | ~4 | ~8–10 | ~4–5 | ~5–6 |
| Down syndrome (live birth) | 1 in 1,250 (0.08%) at 25 | ~1 in 25–30 (3–4%) at 45+ | ~1 in 1,250 | ~1 in 1,100 (negligible independent effect) |
| Trisomy 13 / 18 | <1 in 5,000 | ~1 in 200–500 | minimal | minimal |
| Any chromosomal abnormality at birth | ~0.2–0.3% | ~5%+ | ~0.2–0.3% | small independent rise |
(child typically survives to adulthood and can reproduce)
| Outcome | Mother 20s | Mother 50s† | Father 20s | Father 50s |
|---|---|---|---|---|
| Autism spectrum disorder | ~1.5% | ~2.0–2.5% | ~1.5% | ~2.5–2.8% (≈1.7–2.2× of 20s) |
| Schizophrenia | ~0.5–0.7% | mild / inconsistent | ~0.5% (1 in 198) | ~1.6% (1 in 61) |
| Bipolar disorder | ~1.0% | ~1.0% (no clear effect) | ~1.0% | ~2.5–2.8% (≈2.8× of 30–34) |
| ADHD (lifetime) | ~9% | ~9% | ~9% | weak/mixed when controlled for maternal age |
| Congenital heart defects (any) | ~9 / 1,000 | ~10 / 1,000 | ~9 / 1,000 | ~11–12 / 1,000 (OR ~1.27 at ≥40) |
| Achondroplasia | baseline (~1 / 25,000) | baseline | ~1 / 100,000 | ~1 / 8,000 (≈12×) |
| Apert syndrome | ~1 / 50,000 | ~1 / 50,000 | ~1 / 100,000 | ~1 / 25,000–30,000 |
| Childhood acute lymphoblastic leukemia | ~1 / 2,000 by age 15 | ~1 / 2,000 | ~1 / 2,000 | ~1 / 1,400 (modest rise) |
†Mother-50s natural conception is rare; numbers above 45 are extrapolated and assume own eggs. Donor-egg pregnancies at 50 carry chromosomal risk of the donor's age, not the gestational mother's.
Primary sources: Magnus et al. (BMJ 2019, Norway miscarriage register, n=421k); Morris et al. (Down syndrome by maternal age); Malaspina et al. (Jerusalem schizophrenia cohort); de Kluiver meta-analysis (paternal age & psychiatric disorders); du Fossé et al. (Hum Reprod Update 2020, paternal age miscarriage meta-analysis); Goriely & Wilkie (FGFR2/FGFR3 PAE disorders).
