Males are normally bigger than females – otherwise there are no significant differences in personality or suitability. Claude (my new best AI friend) has analysed our latest survey below – looking at 1076 dogs.

People think females will be gentler, softer, less messy, less likely to pee on car tyres….. whatever the reason for the bias there is a strong bias in favour of female dogs.

Our research shows regularly and repeatedly that our early desexed dogs are pretty much gender neutral, the boys don’t scent mark excessively and the only repeatable difference is that males are – usually but not always – bigger

Sex Differences in Kate’s Family Pets — 2025 Survey

Source: 2025 Health and Longevity Survey (n=1,076 dogs with full data; 538 male, 538 female). Breeds include Standard and Mini Groodles, O’Connell Retrievers, Labradoodles and Cavadoodles. Personality measured via MCPQ-R subscales. All percentages rounded to one decimal place.

1. Size

Males are substantially larger than females. Mean estimated midpoint weight: males 18.5 kg, females 15.6 kg (t=8.94, p<0.001). The difference is highly statistically significant.

2. Temperament (MCPQ-R)

Personality subscale scores are very similar between sexes. Females score marginally higher on Extraversion, Motivation, Training Focus, and Neuroticism; Amicability is essentially identical. Only the Training Focus difference approaches conventional significance (p=0.04), but the effect size is negligible (~1.4 percentage points).

Note: the Ley et al. (2009) validation study found no significant association between dog sex and any MCPQ-R subscale. These results are consistent with that finding.

3. Suitability and Issues Flagged

Owner-reported suitability is near-identical for both sexes: 98.7% of male owners and 99.1% of female owners rated their dog as a suitable choice for their environment.

Temperament was flagged as an issue by 0.7% of male owners and 0.6% of female owners. Size was flagged by 0.7% of male owners and 0.2% of female owners — consistent with males being larger on average.

Summary

The clearest sex difference in this dataset is physical size: males are on average ~3 kg heavier than females (18.5 kg vs 15.6 kg). Personality as measured by the MCPQ-R is very similar between sexes, with no subscale showing a meaningful or statistically robust difference. Suitability ratings and problem rates are also nearly identical, with the small excess of size issues among males in keeping with their larger body size.