Table 2.

Descriptive statistics of variables

Variable	Total		First child-Girl		First child-Boy		P value
	N	% or Mean	N	% or Mean	N	% or Mean
Second birth							0.000a
No	1409	67.06	604	59.27	805	74.40
Yes	692	32.94	415	40.73	277	25.60
Survival time	2101	69.003	1019	65.003	1082	75.003	0.000b
Fertility intention
Intended number of children	2101	1.84	1019	1.87	1082	1.81	0.004b
Presence of son preference							0.000a
No	1468	69.87	789	77.43	679	62.75
Yes	633	30.13	230	22.57	403	37.25
Individual characteristics
Age	2101	33.68	1019	33.37	1082	33.97	0.479b
Age at first childbirth	2101	23.69	1019	23.77	1082	23.61	0.054b
Year of first childbirth							0.522a
2000 and after	1349	64.21	671	65.85	678	62.66
1980s and 1990s	752	35.79	348	34.15	404	37.34
Hukou type							0.308a
Non-rural type	809	38.51	381	37.39	428	39.56
Rural type	1292	61.49	638	62.61	654	60.44
Education							0.001a
Elementary school and below	86	4.10	24	2.36	63	5.74
Middle school	1094	52.10	543	53.29	551	50.97
High school/technical secondary school	450	21.43	223	21.88	227	21.00
Junior college	289	13.76	150	14.72	139	12.86
College and above	181	8.62	79	7.75	102	9.44
Existing childbirth status
Prior abortion							0.004a
No	1934	92.05	956	93.82	978	90.39
Yes	167	7.95	63	6.18	104	9.61
Family environment
Number of paternal siblings	2101	2.03	1019	2.02	1082	2.03	0.900b
Presence of parents-in-law							0.291a
No	230	10.95	104	10.21	126	11.65
Yes	1871	89.05	915	89.79	956	88.35
Regional factor							0.115a
Central Shaanxi	1120	53.31	549	53.88	571	52.77
Southern Shaanxi	537	25.56	273	26.79	264	24.40
Northern Shaanxi	444	21.13	197	19.33	247	22.83

³Different than other means in Table 2, these values are medians for asymmetrically distributed continuous data of survival time.

^aPearson’s chi-squared test of independence between a certain variable and the sex of first child.

^bOne-way analysis of variance (ANOVA) to compare means of the two samples by sex of first child.