Female Labour Market Situation and Timing of the First Birth in Spain. (draft) Alfredo Ariza Arantza Ugidos Universidad del País Vasco 26 February 2002 Abstract Using the Spanish Household Survey Data, we explore the determinants of the timing of the first child in Spain. Our aim is to determine the impact of income, wages and labour market situation in the decision of entry to motherhood. We estimate a discrete-time duration model, controlling for sample selection bias and unobserved heterogeneity. Our results show that employed women delay their first birth relative to women out of the labour force. Female wages have a positive effect on the hazard of having a first child. Those women whose partners have higher earnings have shorter birth interval.