Every fact on this site, with its evidence grade, its caveats and a link to the source.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
Children and pregnancy / Measured in people or real products
About half of children's diaper-rash creams (13 of 28) and a third of children's sunscreens (10 of 29) listed fragrance.
Weak evidence.
Caveats
Small category counts; label count only. Sunscreen share is market-specific: 64.9% (87/134) of Danish children's sunscreens and sun sprays listed fragrance or a named allergen (Botvid 2023), so 'a third of sunscreens' should not be generalized beyond Brazil; diaper creams were not reported separately in Denmark.
Source: Uber 2024, Jornal de Pediatria (Rio de Janeiro) Link to this fact
Children and pregnancy / Measured in people or real products
In 130 Danish and Finnish mothers, phthalate breakdown products were reported in essentially every breast milk sample (95-100% for each of the six measured) — but an independent, more contamination-controlled US study (Hines 2009) found the analogous class of monoester phthalate metabolites in under 10% of milk samples from a separate cohort, and declined to report its own milk hydrolytic-monoester data (which would include MEP) as likely contamination-inflated.
Weak evidence.
Caveats
1997-2001 samples; composite home-collected milk; phosphoric acid was not added at collection 'due to logistics' (this page's own Methods/limitations), a known contamination risk for hydrolytic monoesters. Hines 2009 (EPA/CDC, tighter contamination controls) found the analogous metabolite class in <10% of milk samples and withheld its own milk hydrolytic-monoester data on contamination grounds. US EPA systematic review (Radke 2018) separately excluded this study's milk data as a critically deficient exposure matrix.
Source: Main 2006, Environmental Health Perspectives Link to this fact
Children and pregnancy / Measured in people or real products
Baby boys whose mothers' milk contained more dibutyl phthalate had slightly lower free testosterone at 3 months (about 15% lower per 10-fold rise). For diethyl phthalate, the fragrance phthalate, the link was with higher SHBG, and its free-testosterone trend was not significant. These are correlations in 96 boys, not proof of harm.
Weak evidence.
Caveats
MBP–free T r = −0.22 (p = 0.033); mEP–free T r = −0.19 (p = 0.07, NS). US EPA review excluded this study (breast milk critically deficient as an exposure matrix for short-chain phthalates) and rated infant-testosterone evidence indeterminate (Lin 2011: MEP r = −0.10). 46% of Danish mothers used breast pumps.
Source: Main 2006, Environmental Health Perspectives Link to this fact
Children and pregnancy / Measured in people or real products
In one early, small US study, boys in the highest phthalate group had about 4 to 10 times the odds (3.8-10.2) of a shorter-than-expected anogenital distance than the lowest group, depending on the phthalate. A larger (N=753) follow-up by the same group found much smaller effect sizes for the one phthalate class (DEHP) that replicated, and did not test comparable categorical odds ratios.
Weak evidence.
Caveats
Single small cohort with very wide CIs (MEP OR 3.8, 1.03-13.9); US EPA rated this cohort's AGD data (extended n=106) low confidence. The DEP (MEP) part did not replicate in three larger cohorts, including the same group's own N=753 TIDES follow-up (Swan 2015), which also found smaller continuous effect sizes for the metabolites that did replicate (DEHP: beta -1.12 to -1.43 in TIDES vs -3.50 to -5.13 in this cohort, per Swan 2015's Discussion), consistent with lower current-day exposure. Quote as one small study's result only; prefer the EPA review or Swan 2015 for general claims.
Source: Swan 2005, Environmental Health Perspectives Link to this fact
Children and pregnancy / Self-reported survey
In a US survey, parents reported that 7 in 10 children aged 12 and under (219 of 312) had used makeup or body products such as face paint, glitter, nail polish or body spray, including more than half of children aged 3 or younger (48 of 84).
Weak evidence.
Caveats
207 self-selected parents recruited mostly online in NYC/Boston/Houston; not nationally representative; ~60% of raw responses excluded as spam/fraud. Partial external check: in a Brazilian clinic survey (Melo 2020) per-category color-cosmetic rates matched Medley's (lipstick 18.8% vs lip ≈21%, nail 22.4% vs ≈22%), but the 70% total is driven by body products (face paint, glitter, bath bombs) that Melo did not ask about, and Melo found make-up in only ≈3% of infants, so the under-3 figure reflects body products, not make-up.
Source: Medley 2023 Link to this fact
Children and pregnancy / Self-reported survey
Among US children who used makeup or body products, about 1 in 8 used them daily, about 1 in 5 wore them for 8 hours or more, and about 1 in 3 had swallowed some in the past year.
Weak evidence: Parent report for 217 child users; ingestion differed sharply by ethnicity (41% vs 11%), possibly a question-wording effect.
Source: Medley 2023 Link to this fact
Children and pregnancy / Self-reported survey
Most US children who use makeup also use products made for adults: only about a third (36%) used mostly children's products.
Weak evidence.
Caveats
Parent estimate of product share; small non-representative sample. Applies to makeup only: for cleansers, a Brazilian clinic survey (Melo 2020) found the majority used children's products (children's soap 56.5%, children's shampoo 65.9%; adult soap 37.3%, adult shampoo 27.2%, rising with age), so do not write 'most children use adult products' generally.
Source: Medley 2023 Link to this fact
Children and pregnancy / Self-reported survey
In a US survey, boys and girls who used makeup or body products used fragrance products (perfume, cologne, body spray) at the same rate, about 31%.
Weak evidence.
Caveats
Scent-purpose products only; cleansers excluded, so not a fragrance-exposure prevalence. Indirect support for sex parity: in Melo 2020 (Brazil, 182/276 perfume users, 126 girls) at least 56/150 boys (≥37%) used perfume, so perfume is not a girls-only product; but the Brazilian level (66% of all children) is 3x the US level (≈21%), so the ~31% figure must not be generalized.
Source: Medley 2023 Link to this fact
Children and pregnancy / Self-reported survey
The only population study of lavender and tea tree oils and hormone problems in children (556 US children) was too small to rule out a risk: regularly exposed children had 2.8 times the rate of endocrine diagnoses, with a 95% confidence interval from 0.35 to 22 times.
Weak evidence: Not statistically significant; parent-reported diagnoses; self-selected natural-product users; 9 events. Supports 'not ruled out', not 'causes'.
Source: Hawkins 2021, International Journal of Pediatrics and Adolescent Medicine Industry-funded Link to this fact
Children and pregnancy / Measured in people or real products
In 2007, US government (NIEHS) scientists described three boys aged 4–10 who developed breast tissue while using products containing lavender oil or lavender and tea tree oil (a homemade balm, hair gel and shampoo, soap and lotions); in each case it went away within months of stopping the products.
Weak evidence: 3 case reports, dechallenge only, no rechallenge, products not analyzed; causation contested (BASF guideline tests negative for linalool/linalyl acetate; Braunstein 2023 review).
Source: Henley 2007, New England Journal of Medicine Link to this fact
Children and pregnancy / Review of other studies
In the reported cases, children had been using lavender-scented products regularly (violet-water colognes, shampoos, soaps, baby bath, lotions) or sat beside a classroom diffuser, and breast growth went away after the products were stopped; early breast growth in children often goes away on its own, so this does not prove cause.
Weak evidence.
Caveats
Case reports with dechallenge only; no comparison group; at least one of the violet-water colognes declared and contained no essential oil by an industry analysis (Giroux & Orjubin 2020). Linklater 2015's own transient alpha-fetoprotein/prolactin elevation resolved on its own over the same 12 months, for an unrelated physiological reason (infant liver immaturity) the authors themselves cite — a concrete illustration, from inside this same case, that concurrent findings can normalize without being caused by the product change.
Source: Hawkins 2020, Complementary Therapies in Medicine Industry-funded Link to this fact
Children and pregnancy / Measured in people or real products
Four prepubertal children (three girls with early breast development and one boy with breast growth) whose doctors recorded continuous use of products they identified as containing lavender saw the breast tissue disappear within three to six months of stopping the product.
Weak evidence.
Caveats
Four uncontrolled case reports, dechallenge only, no product analysis by the authors and no chemical measured in any child; both conditions can resolve spontaneously. An essential-oil industry analysis later reported the boy's violet-water cologne declared and contained no essential oil (DEP, alpha-isomethyl ionone and azo dyes instead), and one girl's baby bath only 'very low' lavender oil (unquantified).
Source: Ramsey 2019, The Journal of Clinical Endocrinology & Metabolism Link to this fact
Children and pregnancy / Self-reported survey
At one Miami children's hospital, 16 of the 24 children seen over seven years for unexplained early breast growth had been using lavender-scented products; 14 of the 16 were Hispanic and the products were violet-water colognes of a kind often applied to babies.
Weak evidence.
Caveats
Clinic case tally with no unexposed comparison group and no use-prevalence denominator; a clinic aware of the lavender hypothesis will ask about lavender; one violet-water cologne from this clinic's case reports declared and contained no essential oil by an industry analysis. Diaz 2016 (2015, same hospital, corresponding author Alejandro Diaz also a co-author here) reported 3 boys with the same outcome in the years just before this tally's window; those 3 cases are almost certainly a subset of this 16/24 figure, not additional to it, so this figure and Diaz 2016 should never be added together.
Source: Ramsey 2019, The Journal of Clinical Endocrinology & Metabolism Link to this fact
Children and pregnancy / Measured in people or real products
One of the four children had never used a lavender product at all: she sat beside a classroom lavender oil diffuser that ran all day for a year, and her breast tissue regressed three months after the diffuser exposure stopped.
Weak evidence: Single case report, no air measurement was made in the classroom, and measured indoor terpene levels elsewhere are far below the concentrations that were active in the cell assays.
Source: Ramsey 2019, The Journal of Clinical Endocrinology & Metabolism Link to this fact
Children and pregnancy / Measured in people or real products
In the same 2018 NGO test, a children's shampoo had 24 unlabeled chemicals flagged for health hazards (17 on the fragrance-industry list), and a baby shampoo had 6.
Weak evidence: Counts, not amounts; single samples; not peer reviewed; not a risk ranking.
Source: BCPP 2018 Link to this fact
Children and pregnancy / Measured in people or real products
In a Danish–Finnish study (hormones measured in 96 of 130 baby boys), some phthalates in mothers' breast milk went with hormone changes at 3 months that point to weaker male-hormone action (higher SHBG; lower free testosterone for dibutyl phthalate only).
Weak evidence.
Caveats
Association; hormones in 96 boys; mEP (DEP) free-T link not significant (p = 0.07); 46% of Danish mothers used breast pumps; US EPA review excluded this study (milk critically deficient as exposure matrix) and rated infant testosterone indeterminate. Cite the primary, not the thesis, which inverted the direction.
Source: Main 2006 Link to this fact
Children and pregnancy / Self-reported survey
Children's lipstick, nail polish and eyeshadow use was about the same in a Brazilian hospital survey and a US parent survey (roughly 19-22%, 22% and 11-13%), but perfume use was three times higher in Brazil (66% vs about 21%).
Weak evidence.
Caveats
Our cross-study arithmetic (Medley per-user rates re-based to all 312 children); different definitions ('perfume' vs 'fragrance products primarily for children'), ages (<=14 vs <=12) and sampling.
Source: Melo 2020, Revista Paulista de Pediatria Link to this fact
Children and pregnancy / Self-reported survey
Every one of 13 Washington DC childcare facilities that reported health data had at least one child with physician-diagnosed asthma, with a typical (median) facility rate of about 10%.
Weak evidence: Center-Director-reported, not chart-confirmed; no exposure-outcome link tested; n=13.
Source: Quirós-Alcalá 2016, Environmental Research Link to this fact
Children and pregnancy / Measured in people or real products
Three more boys (ages 9-11) developed breast tissue while using lavender-labeled products, a shampoo or an 'agua de violetas' cologne sprayed on by a parent since early childhood; in each case it resolved within about 4 months of stopping the product.
Weak evidence.
Caveats
Three uncontrolled case reports, dechallenge only, no rechallenge; same hospital and a shared corresponding author (Alejandro Diaz) as Ramsey 2019's later clinic tally, so this is not an independent replication of the case count.
Source: Diaz 2016, Journal of Pediatric Endocrinology and Metabolism Link to this fact
Children and pregnancy / Measured in people or real products
A 14-month-old girl in Melbourne, Australia developed breast tissue while being given five different lavender-scented infant products every day (wipes, shampoo, body wash, cream and lotion); it went away after the products were stopped, and this case has no connection to the better-known United States case series.
Weak evidence.
Caveats
One case report (letter to the editor), dechallenge only, no rechallenge, no product testing; the exposure was identified only after the family saw a documentary about this exact link, not through routine clinical questioning.
Source: Linklater & Hewitt 2015, Journal of Paediatrics and Child Health Link to this fact
Information, not medical advice. See also: myths we won’t tell you.